As a member of the Mulder family, William "Bill" Mulder was the father of Fox and Samantha Mulder as well as the husband of Teena Mulder. He worked for the State Department and later for an offshoot of that organization, known as the Syndicate. (TXF: "Colony", et al.)
Work for the State DepartmentEdit
While working in the State Department, William Mulder found that the choices that needed to be made were highly complicated. (TXF: "Anasazi") He would often travel by road, while working at the State Department. (TXF: "The Blessing Way")
One of the men that Mulder worked with was the Cigarette Smoking Man. Together, they dreamed that computers would someday exist, ignorant of the fact that such technology would one day be home appliances capable of the most technical espionage. (TXF: "Anasazi") In about 1948, William Mulder and the Cigarette Smoking Man began working on a highly classified Project together at the State Department. (TXF: "Two Fathers") The Project dated back to Roswell in 1947. (TXF: "One Son", "The Truth") Mulder would continue to work on the Project with the CSM for about the next twenty-five years, until around 1973. (TXF: "Two Fathers")
Another of William Mulder's friends who worked with him at the State Department was Alvin Kurtzweil. Both were disenchanted with their work, although Mulder's disenchantment outlasted Kurtzweil's. (The X-Files Movie)
In the 1950s, William Mulder and men like him were instructed by the government to gather genetic data on the general populace for the purpose of post-apocalyptic identification, due to the threat of nuclear holocaust at that time. Mulder helped collect the data, so that former Nazi scientist Victor Klemper had access to a DNA database of nearly everyone who had been born since 1950, but Mulder strenuously objected once he realized that Klemper was using the medical data in an effort to create a human/alien hybrid. This work was officially known as Operation Paper Clip. (TXF: "Paper Clip") Many names of doctors were connected to both William Mulder and the Cigarette Smoking Man; one of these doctors was Eugene Openshaw, a Nobel winner for early works in genetics. (TXF: "Two Fathers")
While working at the State Department in 1952, Mulder learned that three patriotic veterans – Edward Skur, George Gissing and Terrill Oberman – had been working for the State Department when they had been transformed into something inhuman by a government conspiracy that included Roy Cohn and Senator Joseph McCarthy. Mulder thereafter learned that both Gissing and Oberman had killed themselves because they found it too difficult to live with what they had been turned into. Mulder also discovered that, in the conspiracy's attempt to cover up the truth of what they had done to Skur, he was labeled as a Communist before being reported to have killed himself and resigned to someplace where no one would look for him.
One morning of 1952 after Edward Skur escaped, Mulder visited a doctor's house in Chevy Chase, Maryland and tried to save the doctor – who had been attacked by Skur – but to no avail, as Mulder was too late. Despite the fact that his family and career would be risked if Mulder was caught trying to expose the truth about Skur and the government conspiracy, he nevertheless made an attempt to let the truth be known and, to this end, he left a clue in the doctor's house that summoned an investigator of the doctor's death, FBI Agent Arthur Dales, to the Hoot Owl.
There, Mulder was sitting in a darkened booth upon Dales' arrival. Mulder was originally mistaken by Dales as being Skur himself and as having murdered the doctor, but Mulder corrected the FBI agent, adding that he had come to warn Dales about Skur. Mulder continued to do exactly that, cautioning Dales that Skur would try to kill him and telling the FBI agent that Skur was actually not a Communist but the last of three men who had been operated on. Mulder also informed Dales about the government conspiracy, saying that he was no longer willing to have their crimes on his conscience and that Skur wanted vengeance for what they had done to him. After Mulder mentioned that Skur thought both Dales and his FBI partner, Hayes Michel, were part of the conspiracy (the two agents having previously arrested Skur for allegedly being a Communist), Dales realized that Skur had targeted Michel, who was killed at home by Skur moments later. Mulder's information nevertheless subsequently helped Dales with the case and led him to find the X-files.
Mulder thereafter cooperated with the conspiracy members. At night, he arrived in the back of a car outside the Skur residence with Roy Cohn and other men, shortly after Agent Dales had been talking to Mrs. Skur, and sat next to Dales, looking uneasily at him, after Cohn ordered the FBI agent to get in the car. Later that night, Mulder accompanied Cohn and Agent Dales into the office of FBI Director J. Edgar Hoover, at FBI Headquarters, but both Mulder and Cohn were unexpectedly expelled from the room by Director Hoover. Following Dales' conversation with Hoover, Mulder sat in the front passenger seat of the same car that he had previously been in, while Dales still sat in the back of the car and the only other person inside the vehicle was the driver. After the driver instructed Dales to meet Skur inside the bar and to put him at ease in preparation for the entrance of the other men, Mulder was asked by Dales if the reason he had sought out the FBI agent was to make Dales his "stalking horse", but Mulder gravely declared that he followed his orders. Along with the driver, Mulder subsequently monitored the audio of Dales' meeting with Skur. Mulder was about to open his door, when Skur began to attack Dales, but was convinced by gestures from the driver to wait until the sounds of struggle had subsided. Mulder then led the way as he and the driver hurried inside the Hoot Owl, only to find that Dales had handcuffed Skur to the bar.
In daylight shortly thereafter, Mulder drove the same car in which he had been a passenger, maneuvering the vehicle along a long, straight rural road while Skur sat in the front passenger seat, handcuffed to the vehicle. Mulder abruptly stopped the car and exited the vehicle, tossing keys to a confused Skur who then unfastened his restraints and continued to drive in the same direction that the vehicle had been going as Mulder walked the other way, having let the killer go free in the hope that (by letting Skur live) the truth of the crimes that had been committed against him and the others might someday be exposed.
Military Career and Researching the Alien VirusEdit
As a young man, William Mulder served in the military, as did Alvin Kurtzweil. Like Kurtzweil, Mulder was recruited for a Project and was told by a group that the Project involved a virus as biological warfare. The contagion was actually alien in origin. (The X-Files Movie)
On August 19, 1953, Mulder was a member of a group of Washington officials who traveled to Pearl Harbor, Hawaii to recover information from an irradiated survivor of the Zeus Faber, a submarine whose captain had been infected with the alien virus. Despite the ill crewman expressing that he refused to inform the US Navy of what had happened, Mulder assured the survivor that the reason he and his group had come all the way from Washington was to hear the survivor's story and ensure that justice was served. Mulder was then instrumental in questioning the survivor about the incident aboard the Zeus Faber but he looked to the Cigarette Smoking Man – another of the three men who were debriefing the survivor – upon the crewman asking Mulder specifically whether he could be trusted to ensure that the truth was exposed. (TXF: "Apocrypha")
In 1961, Teena Mulder had an affair with the CSM and became pregnant with Fox Mulder, whom Bill Mulder would continue to raise as his own son. (TXF: "Demons", "The Sixth Extinction II: Amor Fati", "The Truth")
According to unconfirmed evidence later collected by Melvin Frohike, William Mulder served with the Cigarette Smoking Man in the Center For Special Warfare at North Carolina's Fort Bragg, in 1962. On October 30 of that year, Mulder was supposedly happy that his baby son had just said his first words and was in the facility's barracks while the CSM was reading The Manchurian Candidate to himself. Apparently, Mulder asked the CSM why he didn't simply go and see the movie based on that book, but the CSM remarked on his own extreme preference for books rather than movies. After a Corporal notified the CSM that General Francis requested his immediate presence, Mulder told the CSM that his own son had just spoken his first words and showed a photograph of his son and wife to the CSM, who asked what the baby's first words had been. Supposedly, Mulder claimed they had been the initials "J.F.K." and this provoked a laugh from the CSM. According to Frohike's evidence, Mulder placed the photograph in a special place as the CSM watched (immediately before the CSM left the barracks) and Mulder's prized photograph was somehow later acquired by the CSM, who retained the picture until at least April 4, 1968. (TXF: "Musings of a Cigarette Smoking Man")
Family Life and Syndicate InclusionEdit
William Mulder once had a picnic with the other members of his family, Alvin Kurtzweil and three other picnickers. All eight individuals were photographed together at a picnic bench, with William Mulder sitting on the bench next to his wife. (The X-Files Movie)
In about 1972 or '73, Mulder was photographed alongside other members of the Syndicate, outside the Strughold Mining Company in West Virginia. He stood on the left of this image, between the Cigarette Smoking Man and Victor Klemper. (TXF: "The Blessing Way", "Paper Clip") Another of the men who was present for this image was the Well-Manicured Man, who William Mulder had known since they were both young men. (TXF: "Paper Clip")
In 1973, William Mulder was again photographed with the CSM but the two men were alone together, this time, and were facing each other as opposed to the camera. They were apparently mid-argument. (TXF: "Two Fathers", "One Son")
In October 1973 or thereabouts, Mulder bought an Electrovac Princess vacuum cleaner for his wife. (TXF: "Paper Hearts") He had a habit of eating sunflower seeds and, repeatedly, the sound of him doing so, in the Mulder family study, was the first sound that his son heard after waking up from nightmares that influenced Fox Mulder to think he was the only person left in the world. (TXF: "Aubrey")
Despite being in or near the Strughold Mining complex, William Mulder never went home wearing a miner's cap. (TXF: "Paper Clip") He did, however, bring his Syndicate colleagues home on at least one occasion and Teena Mulder consequently met them. (TXF: "The Blessing Way") At least once, William Mulder – being a competent water-skier – went water-skiing with the CSM on a stretch of water near the Mulder family's summer house in Quonochontaug, Rhode Island. (TXF: "Talitha Cumi")
Disagreement with the SyndicateEdit
In 1973, the Syndicate members agreed to cooperate with a race of alien colonists that planned to re-colonize the planet Earth by unleashing the alien virus on a major scale, and the human conspirators decided on doing this by a majority vote that they took, but William Mulder objected to the idea of the Syndicate allying themselves with the alien colonists. Mulder was against the prospect of the Syndicate allowing alien colonization to begin and said that their doing so would be the group's "tragic mistake." He was also against the idea of using innocent women as test subjects in the effort to create an alien/human hybrid so that the Syndicate members would survive colonization, as genetic hybrids themselves. Mulder was, however, the lone dissenter. (TXF: "One Son") Unlike the other Syndicate members, he refused to believe that survival was the ultimate ideology. (TXF: "One Son", The X-Files Movie) The other Syndicate members voted against him, because they believed that resisting colonization would be futile. (TXF: "Two Fathers") The group's vote also changed Mulder's working environment, as it meant that the Syndicate would no longer cleave to any government agency but would instead operate privately, on their own Project. (TXF: "One Son")
William Mulder railed at the rest of the group and their plans, even as the process had begun and the group had agreed to reluctantly sacrifice members of their own families because the aliens, who distrusted their human collaborators, insisted on such sacrifices as human collateral. (TXF: "One Son", "The Truth") In 1973, William Mulder strode up to a gathering of other Syndicate members in El Rico Air Force Base and, around the same time, he stood with the group as they witnessed the other members' family members being taken by the aliens from the same base.
Mulder subsequently had the idea of using alien DNA – from an alien fetus that the colonists had exchanged in return for the family members – to create a vaccine against the alien virus; the successful development of such a vaccine would save Earth's human population. This idea influenced Mulder to go along with the other Syndicate members. Having previously failed to realize that not only the Syndicate members themselves but also those close to them would survive colonization, William Mulder now realized not only this but also that the survivors would live to see their family members return. (TXF: "One Son")
Role in Daughter's Abduction and Subsequent WithdrawalEdit
Contrary to his refusal to believe that survival was the ultimate ideology, William Mulder sacrificed his daughter, Samantha, and let her not only be abducted but also be taken to a cloning program. He was motived by a single purpose – that his daughter would become one of few survivors of the viral holocaust, if she became a genetic hybrid herself. William Mulder chose hope over selfishness and invested that hope in his children, the only future that he had. His hope for his son, Fox, was that he would uncover the truth about the project, stop it and essentially fight the future. (The X-Files Movie)
According to memories or hallucinations that Fox Mulder experienced years later, William Mulder argued with both his wife and the CSM shortly before Samantha Mulder was abducted. (TXF: "Demons") However, William Mulder ultimately gave up Samantha, his own eight-year-old daughter. (TXF: "One Son", "The Truth")
He was late to understand the necessity of such a familial sacrifice, so Samantha was abducted from the Mulder family home, right in front of her brother, Fox. (TXF: "One Son") On the night of her abduction in November 1973, William Mulder and his wife had said that Samantha could watch a particular movie that she wanted to see but had left Fox Mulder in charge as they had gone to visit their next door neighbors, the Galbrands. (TXF: "Little Green Men", "Paper Hearts")
An extraordinary amount of effort was put into the search for Samantha Mulder, owing to the fact that William Mulder worked at a high level in the government, and even the Treasury Department got involved. However, no evidence was found and, later in 1973, the Cigarette Smoking Man signed a document that effectively called off the search. (TXF: "Closure")
William and Teena Mulder subsequently divorced. (TXF: "Talitha Cumi", "Paper Hearts") Following this, William Mulder bought a two-story house in Martha's Vineyard, West Tisbury, Massachusetts, located six miles from his former family home in Chilmark. (TXF: "Paper Hearts", et al.)
William Mulder had become estranged from his son by November 1990. In that month, Edward Skur died while repeating the name "Mulder" and Fox Mulder – investigating this death in his current capacity as an FBI agent – began to learn of his father's involvement with Skur and the conspiracy to hunt for suspected Communists. As Agent Mulder and his father had become estranged by this point, William Mulder was not approached by his son for information and Agent Mulder instead sought after the reluctant assistance of now-retired Special Agent Arthur Dales, who slowly recalled what he knew of William Mulder and how they had become involved with Skur. Agent Mulder found it difficult to believe that William Mulder had collaborated with the conspirators and remarked that he had let them dictate his conscience, but Dales thought that Agent Mulder was being too harsh on his father. Dales was at a loss for why Skur had been saying the name "Mulder" when he had died and was unaware that the killer had been living freely specifically because William Mulder had allowed Skur to escape, although Dales had considered the possibility that Skur had been let loose by "some poor innocent bastard, somebody with a conscience." (TXF: "Travelers")
According to the evidence that Frohike gathered, William Mulder was mentioned by the CSM to Deep Throat on December 24, 1991, shortly after they learned that a UFO had crashed and that its alien occupant had been recovered but was in critical condition; the CSM, realizing that Deep Throat wanted him to kill the alien occupant, stated that such a living alien subject could advance "Bill Mulder's project" by decades. Apparently, Deep Throat countered by citing Security Council Resolution 1013 and went ahead with killing the alien himself. (TXF: "Musings of a Cigarette Smoking Man")
Subject of a Dream and Later LifeEdit
In 1994, when attempting to persuade autistic murder suspect Roland Fuller to divulge his dreams, Agent Mulder claimed to Fuller that he himself had experienced a dream in which his father had temporarily featured. According to Mulder, he had dreamt that he had been swimming in a pool and could see his father underwater but lost sight of him and couldn't find his father when he tried to leave the pool, while an observing man tried to ask him questions that he preferred not to answer. (TXF: "Roland")
One afternoon in 1995, William Mulder received a puzzling phone call from a clone claiming to be Samantha Mulder. He then tried to gather the other members of the family, calling Teena Mulder and unsuccessfully attempting to contact their son. He also contacted FBI Assistant Director Walter Skinner, who finally let Mulder know that his father had been trying to contact him and that there had been a family emergency. William Mulder spoke to his son when Agent Mulder called him. He recalled that he had received a strange call earlier but did not go into further details about it yet, stating that he would know more by the time that his son came to his home.
At night, he greeted Agent Mulder on the porch of his own house, where he was smoking a cigarette and had been sitting alone on a seat in the dark. He initiated a hand-shake with his son and told the younger Mulder that his mother needed some time and had wanted him to come. William Mulder admitted that it was a difficult time and that he appreciated his son's arrival at such short notice. When asked by his son what the emergency pertained to, William Mulder cryptically implied that the certainty he had felt concerning Samantha's disappearance had become a comfort that had allowed him to move on and that he had buried his memories of the incident after so much had been destroyed, never expecting a resolution. Finally, he told Agent Mulder that his mother, who could be viewed from the porch as she talked to another woman, was actually talking to Fox Mulder's sister.
Soon thereafter, the clone commented to Agent Mulder that William Mulder (who the clone referred to as "dad") had seemed like he couldn't think of what to say and had simply sat in the seat where he had been sitting upon his son's arrival. The clone also claimed that, after her abduction, she had been placed with another family and had lost all memory of Samantha's parents. (TXF: "Colony")
After the clone fell off a bridge and into icy water immediately following a hostage trade for Agent Dana Scully, Agent Mulder found it much harder to tell his father what had happened than reporting the same news to AD Skinner. At his son's request, William Mulder visited Fox Mulder's apartment. He was immediately aware, however, that his son had not asked him to come so far just to give him some good news and told his son as much, upon Agent Mulder answering his door to the older Mulder. With a series of questions, William Mulder prompted his son to recount what had happened and wondered whether Fox Mulder realized how the news would affect his mother. His latter query was not directly answered by his saddened son, who instead apologized profusely.
William Mulder started to turn away from the apartment but paused to show his son an envelope that the Samantha Series clone had left at his West Tisbury home, having intended the envelope to be given to Agent Mulder. Leaving the envelope on a table before slamming the apartment door shut behind him, William Mulder exited his son's apartment. The envelope that he had delivered led Agent Mulder to discover that the woman he had thought had been his sister had merely been one of a series of clones. (TXF: "End Game")
On April 13, 1995, William Mulder was visited at home by the Cigarette Smoking Man. Mulder was initially surprised to see the CSM at his door and was curious to know why his visitor had come. Even though the CSM stated that he was there on some urgent business, Mulder began to remind him of their agreement regarding limited contact. However, he was interrupted by the visitor, who remarked that their agreement had been made a long time ago and that there had recently been some unforeseen events.
After the CSM entered Mulder's home, Mulder learned from his visitor that his own son had obtained the MJ documents. He took a seat at a table with the CSM, who poured the two men a drink. Mulder remarked that no-one had been meant to know that the files existed and complained that they should have been destroyed. Pondering the situation, Mulder wondered how it was certain that his son had the documents. When the CSM admitted that the man who had stolen the files had given himself up, Mulder exclaimed, "Oh, God." Mulder then responded to the CSM claiming that the Syndicate was maintaining plausible denial by arguing that his own name was included in the files. Changing the topic of conversation slightly, Mulder hoped in askance that the CSM would not harm Agent Mulder and – even though the CSM seemed satisfied with the FBI agent's present status – William Mulder worried that his own son might learn of his involvement. The CSM regarded Bill Mulder as always having been his own man but encouraged him to deny everything, if his son did indeed find out about his involvement, and left, remarking that it was good to see Mulder and that he looked well.
With another drink in his hand, William Mulder called his son's apartment that night and spoke to his son, urgently insisting that Fox Mulder come to his home as soon as possible. Shortly thereafter, William Mulder greeted his son at his front door with a hug and invited a slightly confused Fox Mulder inside. He closed his front door, locking it securely.
Later sitting with his son, William Mulder remarked that the choices that had needed to be made were now so clear and simple but had been complicated before, although Agent Mulder did not understand what choices the older Mulder was referencing. William Mulder complimented his son by saying that he was smarter than he himself had ever been and stood up to look out a window before turning back to his son. As Fox Mulder was also perplexed by the generalization of this comment, William Mulder clarified that Fox had his own politics and had never "thrown in." The older Mulder then made a comment that his son interpreted as meaning that he was recalling how, in the State Department, he had thrown in and the doctrines of his fellow workers had become his own, making him capable of being held responsible. He warned Fox that he would learn of things and that the words "the merchandise" would come to make sense to him. Admitting that he had been taking some medication, Mulder excused himself from his son's company and headed into his bathroom.
There, William Mulder looked at his own reflection in a mirror and removed a bottle of pills from a wall-mounted cabinet, unaware that Syndicate assassin Alex Krycek was watching him while standing directly behind him. Moments later, Agent Mulder heard a gunshot and jumped at the noise. He raced into the bathroom, to find his father alone, lying on the floor with a trickle of blood running from one corner of his mouth and from an injury on his forehead. A shocked Fox Mulder cradled his father's head in his hands and heard distant tires screech outside. In a hoarse whisper, William Mulder said to his son, "Forgive me". He then died and his upset son crouched over his body, embracing the dead man. (TXF: "Anasazi")
Aftermath and Investigation of PastEdit
Shortly after William Mulder's death, his son placed his deceased body on a sofa in his living room.
Agent Mulder then called Scully with news of his father's death. Even though he told her that "they" had shot his father (in response to an unrelated question), he also told her – when she asked him who his father had been shot by – that he did not know. Scully began to suspect that Mulder himself had shot his father; he realized this when Scully asked him if they had been arguing but he quickly corrected her and added that his father had been attempting to tell him something. Scully claimed that she now believed Mulder but she was worried that he would nevertheless be held accountable for having murdered his father, as he was unsure of who the real shooter had been and had recently been acting irrationally. Mulder argued that his father had been shot with someone else's weapon but an irritated Scully reminded him that, as an FBI agent, he had access to weapons other than his own. When the two agents then met, Scully was insistent that Mulder rest even though he was intent on searching for his father's killer.
Mulder woke, on the morning of April 14, to discover that Scully had taken his gun to FBI Ballistics. She had done so in an attempt to clear his name but Mulder suspected that she was working against him and had taken his weapon because she still thought he had shot his father. She continued trying to collect evidence to prove Mulder's innocence, however.
That night, Agent Mulder not only fought with Krycek – after finding him outside Mulder's apartment building – but also demanded to know whether he had killed William Mulder. Krycek was not forthcoming with an answer so Mulder brutalized him until Scully – who had discovered that Mulder was being influenced by a drug that was being secretly added to the water supply of his apartment building – approached the two combatants, attempting to convince Mulder to back away from Krycek despite Mulder's insistence that Krycek had killed his father.
Scully shot Mulder and he awoke on April 16, confused as to why she had shot him when it was Krycek who Mulder blamed for having killed William Mulder. Scully explained that – if Agent Mulder's theory was correct and he had shot Krycek – there would have been no way to clear his own name in the murder of his father. Scully also expressed that she was sorry about his father, commenting that she had not had a chance to tell Mulder that she was. She also clarified that she had not been certain that Krycek had shot William Mulder and suggested that the same men who had been adding the drug to Mulder's water supply may have been responsible for killing his father.
Shortly after Mulder was taken to a New Mexico quarry where there was rumored to be evidence of the Syndicate's activities, he received a phone call from the Cigarette Smoking Man, who advised an uncooperative Agent Mulder that his father may have told him things that the CSM warned him not to take at face value. When Mulder asked which things the CSM was referring to, the CSM claimed that Bill Mulder had never been an opponent of the Project and had, in fact, authorized it. The CSM implied that Bill Mulder had committed suicide due to his guilt over having authorized the Project but Agent Mulder instead accused the CSM of having sanctioned the murder, even though the CSM insisted that his group had not been involved in the death. Despite Mulder threatening to expose the Syndicate and their Project, the CSM warned Mulder that, if he exposed anything, he would only be exposing his own father. Mulder abruptly ended this call and was then taken to an area where he found many alien-looking bodies that had actually been human test subjects who were referred to, in the MJ documents, as "the merchandise." (TXF: "Anasazi") These bodies were actually those of test subjects experimented on as part of the Syndicate's struggle to create a human/alien hybrid. (TXF: "Paper Clip")
Mulder subsequently went missing and was presumed to be as dead as his father. (TXF: "Anasazi", "The Blessing Way") After Scully was suspended from the FBI due to having been absent from a meeting in AD Skinner's office, she privately insisted to Skinner that the people who had killed Mulder and his father were not meant to be found despite Skinner stating that the FBI would find the killers. Shortly thereafter, Mulder's body was found and Native American healer Albert Hosteen, who had taken Mulder to the quarry, performed an ancient healing ceremony (known as the Blessing Way) on him, although the healer feared that Mulder's spirit wished to join the spirit of his deceased father and did not want to return to the world of the living.
On the verge of death, Mulder hallucinated that several people whom he had known before they had died were surrounding his body and visiting him, including Deep Throat and his own father. The hallucinatory version of his father said to him;
- "Hello, son. I did not dare hope to see you so soon nor ever again hope to broker fate with a life to which I gave life. The lies I told you were a pox and poison to my soul and now you are here because of them. Lies I thought might bury forever a truth I could not live with. I stand here, ashamed of the choices I made so long ago, when you were just a boy. You are the memory, Fox. It lives in you. If you were to die now, the truth will die. And only the lies survive us."
In response to Agent Mulder asking if his sister was with the gathered deceased, the hallucinatory William Mulder replied negatively and told Fox, "The thing that would destroy me, the truth I felt you must never learn, is the truth you will find if you are to go forward." This apparition then drifted out of Mulder's view.
After Scully acquired proof that Kenneth Soona (the same person who had given Mulder the MJ files) had been killed prior to Mulder's disappearance, she took the information to Skinner and, reminding him that he already had the ballistics data from Mulder's father on file, Scully asked Skinner to run that data against the ballistics from Soona's case to see if both men had been killed by the same weapon. If they had been, it would prove that Mulder had not killed his father and Scully hoped it might also help the FBI to find the actual killer. Skinner refused her suggestion, however.
A funeral in William Mulder's memory was subsequently held in the Garden Of Reflection at Parkway Cemetery in Boston, Massachusetts. The attendees of this ceremony included Teena Mulder, Dana Scully and the Well-Manicured Man. During the funeral service, a minister declared;
- "We are here to mourn the passing of William Mulder, to join in our grief for our loss but to share also the memories of a man whose life was rich and full and who made his family's and his friends' lives richer and fuller as well. Sadly, I've been informed today by the mother of William's children that his son, Fox, could not be here to join us in this time of sorrow."
Scully told Teena Mulder, at this event, that her son would be okay and, soon thereafter, Fox Mulder privately revealed to his mother that he was indeed still alive. He mentioned that he needed to know more about his father, showing her the Syndicate photograph in which William Mulder appeared. Reminding his mother that his father had repeatedly gone traveling while working in the State Department, Agent Mulder wondered where his father had gone to, on these journeys, but his mother claimed she did not remember and pleaded for him to stop quizzing her. Persisting, Fox Mulder presumed aloud that his father had talked with his mother about the work and the Syndicate members. He asked her if William Mulder had ever brought his workmates home, to which Teena Mulder replied positively but stated that she no longer remembered their names. (TXF: "The Blessing Way")
After Agent Mulder revealed to both Scully and Skinner that he was still alive and AD Skinner showed the two agents that he had a digital copy of the MJ documents, Agent Mulder told Skinner that his "cigarette-smoking friend" had killed William Mulder for the tape and had then killed Mulder himself; Agent Mulder explained that he had been a dead man but had returned. Privately, Scully recounted to Mulder that she had gone to his father's funeral and had told his mother that he was going to be okay.
Soon thereafter, Mulder showed the Syndicate photograph to the Lone Gunmen, pointing out his father. Langly and Byers identified the man standing next to William Mulder as Victor Klemper and Scully wondered why Klemper, a former Nazi scientist, would be in a photograph with Agent Mulder's father, but Mulder was also uncertain why this would be. The agents then visited Klemper at his greenhouse and he immediately recognized Mulder's surname, so Mulder explained that Klemper had known his father. After Klemper predicted that he – like his Jewish test subjects – would soon also die, Mulder admitted that his own father was likewise dead and had been killed by the Syndicate. Mulder suspected that Klemper knew why his father had been killed and Klemper confessed that he believed his own former Syndicate colleagues would kill anyone, if doing so would benefit their work. Mulder demanded to know both the details of this work, mentioning that his own father had been involved in it, and whether his father had also been a murderer, but Klemper was largely unforthcoming with any answers, merely directing the agents to the Strughold Mining Company. Following the agents' visit, Klemper called the Well-Manicured Man with news of the incident, describing Mulder as "the son of one of our old colleagues."
Upon entering the complex, Scully asked Mulder what he thought his father might have been doing there but he again claimed ignorance, recalling that his father had never come home wearing a miner's cap. Scully managed to unlock a large, black, high-tech door on a floor that contained a row of similar doors but, before opening this door, she reminded Mulder that his condition had prevented him from attending his father's funeral and expressed her concern that something behind the door might cast a negative light on his father.
After the agents found that the door led to a mountain vault that contained many medical records of abductees and met with Skinner, the agents argued with Skinner about whether to keep the digital copy of the MJ documents, as Mulder wanted to do, or use it to negotiate for the agents' reinstatement at the FBI and the continuance of their safety, a course of action that Skinner preferred. Mulder mentioned that one of the things he hoped to find in the files was an answer to why the Syndicate had killed his father.
The agents subsequently headed back to Klemper's greenhouse but found that he had already been killed by the Well-Manicured Man, who Mulder realized had known his father as they had been pictured together in the Syndicate photograph. The man confirmed that he had known William Mulder since they had both been young men. The Well-Manicured Man then began to reveal that William Mulder had unknowingly aided Operation Paper Clip. Additionally, the Well-Manicured Man not only asserted that the reason Samantha Mulder had been abducted was that her father had threatened to expose the Project but he also warned Mulder that his own life was in danger as he, like his father had done before him, threatened to expose the Project.
Agent Mulder returned to question his mother about the past and quizzed her, this time, on whether – prior to Samantha's abduction – their father had ever asked their mother if she had a favorite or made her make a choice. Despite initially trying to persuade Fox Mulder to relent, Teena Mulder eventually confessed that she had been unable to choose, that the choice had been made by William Mulder and that she hated him for it both then and now, even though he was now dead. (TXF: "Paper Clip") Her statement was brought into question a year later, however, after Agent Mulder underwent an elaborate treatment to recover his lost memories of his sister's abduction and apparently recalled that his mother had not actually been given the choice between her two children, as the CSM had forced her to choose Samantha. The memory retrieval process involved the ingestion of a powerful hallucinogen and it was therefore unclear whether Agent Mulder's memories had been his own. (TXF: "Demons")
After Agent Mulder was asked by self-proclaimed psychic Yappi to leave a room where a murder had been committed, Mulder did so, under duress, and – as Yappi passed Mulder on the way out of the room – Mulder asked the supposed psychic to read a certain thought. Apparently having read Mulder's mind, Yappi slightly jumped back in shock and remarked that the same thought was true of Mulder's "old man", before the self-proclaimed psychic continued on his way. (TXF: "Clyde Bruckman's Final Repose")
After Agent Mulder took Jeraldine Kallenchuk into custody in Hong Kong but was confronted by a gun-wielding Krycek in Kallenchuk's Hong Kong office, Agent Mulder suggested that Krycek use his gun to shoot himself in the head, as Mulder believed Krycek had done to William Mulder. With sarcastic enthusiasm, Kallenchuk likened the situation to "High Noon in Hong Kong."
Krycek managed to flee from Mulder on this occasion but Mulder later encountered Krycek at Hong Kong Airport and assaulted him several times while referring to each blow as a comeback for each of Krycek's victims. As Mulder pointed a gun at Krycek's gut and prepared to attack him with a blow that Mulder intended to be retaliation for his father's murder, Krycek insisted that he hadn't killed William Mulder. Krycek also alleged that he was unaware of the real killer but Mulder reminded him that, either way, he was a liar. (TXF: "Piper Maru")
Shortly thereafter, Mulder called the Syndicate's headquarters and spoke to the Well-Manicured Man, to whom Mulder described Krycek as the killer of his father. Mulder and the Well-Manicured Man then arranged a meeting at which the Well-Manicured Man realized aloud that Mulder was looking for Krycek to kill him in revenge and remarked that Mulder, certainly, had no doubt that everyone could be gotten to. (TXF: "Apocrypha")
In 1996, the Cigarette Smoking Man approached Teena Mulder at her summer house in Quonochontaug, Rhode Island and recollected that he had enjoyed water-skiing with Bill Mulder in the water nearby. Despite admitting that William Mulder had been a good water-skier, the CSM claimed that he had been better at it than William Mulder and alleged that the same could be said about many things. Shortly after this discussion, Jeremiah Smith physically assumed William Mulder's appearance while being interrogated by the CSM. (TXF: "Talitha Cumi")
It was later that year that Frohike began to uncover evidence that involved William Mulder's early interactions with the CSM. Frohike notified Agents Mulder and Scully of the evidence soon thereafter. (TXF: "Musings of a Cigarette Smoking Man")
Also in 1996, John Lee Roche claimed to Agent Mulder that he himself had been the salesman from whom William Mulder had bought the Electrovac vacuum cleaner for his wife in 1973. However, Roche seemingly had trouble recalling if the vacuum cleaner had been a Duchess or Princess model and alleged that he had talked about it at great length with William Mulder, who had apparently had a very difficult time with choosing the right vacuum cleaner. Subsequently, Teena Mulder confirmed for her son that his father had once bought her a vacuum cleaner that she no longer used and Scully established that Roche had been in Boston during most of 1973 but had taken a single sales trip to Martha's Vineyard in October of that year.
Agent Mulder then took Roche to William Mulder's house in West Tisbury, while fooling Roche into believing that the house was the one in Chilmark from where Samantha Mulder had been abducted in 1973. Roche alleged that he had sat on a particular couch in the house, when William Mulder had bought the vacuum cleaner, and that – on the night when Samantha Mulder had been abducted – Fox Mulder had been trying to get his father's gun, moments before Roche had taken Samantha away. Agent Mulder then came clean with Roche's mistake, believing that Roche had somehow managed to enter his dreams of the incident, and Roche subsequently escaped from custody before being killed by Mulder. (TXF: "Paper Hearts")
Shortly after Krycek was captured by Mulder and Scully in 1996, Krycek implicated Luis Cardinal as having been responsible for William Mulder's death, when Krycek claimed to the agents that he wanted to find the same man who had not only killed both William Mulder and Scully's sister, Melissa, but had also tried to kill Krycek. (TXF: "Tunguska")
In 1997, after Agent Mulder was shown evidence that AD Skinner had apparently killed Detective Ray Thomas, Mulder suspected that Skinner had not only killed the detective but had also known when the Cigarette Smoking Man had authorized both the assassination of William Mulder and Scully's abduction. However, Skinner soon managed to persuade Agent Mulder of the truth – that he had been set up by the CSM to appear to be guilty of Detective Thomas' murder. (TXF: "Zero Sum")
It was later that year that Agent Mulder underwent the memory treatment process and his father featured in visions that consequently appeared to him. At one point, Agent Mulder confronted his mother about what had happened and accused her of having had some kind of relationship with the man who had worked with his father, betraying William Mulder. Agent Mulder also asked his mother who his father was, but Teena Mulder was outraged that her son had accused her and rhetorically asked if what he wanted was to kill his father again. (TXF: "Demons")
When Department of Defense employee Michael Kritschgau tried to convince Agent Mulder of the truth as Kritschgau saw it – that Mulder had been hoaxed into believing that aliens were real – Kritschgau mentioned that, as part of the government's effort to cover up the truth, they had fed incredible lies to Mulder's father. (TXF: "Gethsemane") Agent Scully was dying of cancer during this period and, shortly after she essentially introduced Agent Mulder to Michael Kritschgau, her brother, Bill Scully, complained that he had already lost one of his sisters and was now losing another, blaming both losses on Mulder's quest to prove the existence of alien life. Agent Mulder nevertheless sympathized – admitting that he himself had lost not only his own sister but also his father due to his quest – but Bill Scully merely insulted Mulder before leaving him.
Agent Mulder then met another woman who seemed to be his sister. She referred to the CSM as her "father" and claimed that, although she had thought that she knew who her father was, the CSM had told her that he was her real father and that he and her mother had kept that fact a secret in an effort to protect the Mulder family.
Subsequently, Agent Mulder met privately with the CSM, who offered Mulder an opportunity to learn first-hand about the Syndicate's Project and the conspirators themselves, in return for Mulder quitting the FBI and instead working for the CSM, but Mulder profusely declined the deal, reminding the CSM that he had murdered Bill Mulder. (TXF: "Redux II")
In 1998, Alvin Kurtzweil, now a doctor, approached Agent Mulder outside Casey’s Bar & Grill and introduced himself as an old friend of Mulder's father. Later, near Dr. Kurtzweil's apartment, he told Agent Mulder about the alien virus, recounting how – while both himself and William Mulder had been serving in the military, during their young adulthood – they had been recruited for a Project involving the virus. In Casey's Bar & Grill, Agent Mulder doubted that Kurtzweil had known his father, despite Kurtzweil's insistence that they had been old friends. Agent Mulder realized that the two men had indeed known each other when he, back in his apartment, looked out the picnic photograph that included both his father and Kurtzweil.
The Well-Manicured Man later privately provided Agent Mulder with much secretive information about the Project. After telling Agent Mulder that the Syndicate's only defense against the alien virus being reconstituted by the Alien Colonists during colonization was a weak vaccine, the Well-Manicured Man rhetorically asked Mulder whether he understood why the virus had been kept secret and why men like William Mulder – whom the Well-Manicured Man described as an example of "the best men" – had not been able to let the truth be known. The Well-Manicured Man also implied that he thought William Mulder's refusal to accept the Syndicate's belief that survival was the ultimate ideology had been wise. Additionally, the Well-Manicured Man explained why William Mulder had chosen to give up his daughter, Samantha. (The X-Files Movie)
At a Syndicate gathering in 1999, Krycek reminded several group members, who suggested that the Syndicate side with a rebel faction of faceless aliens, that they (the same group members) had voted against men like Bill Mulder because they had always believed that resistance was futile.
Scully subsequently showed Agent Mulder the photograph of his father alone with the CSM and told him that there were names of doctors connected to both men. The CSM, while later narrating these events to Diana Fowley, stated that – if Agent Mulder had previously been unaware of his father's history with the CSM – Mulder was now fueled with names, dates and certainties. The CSM also told Fowley that he could no longer prevent Agent Mulder from learning the sins of both his father and the CSM.
Around this time, Agent Mulder notified AD Skinner about the Syndicate and their effort to create alien/human hybrids, telling Skinner – when he asked if there was proof of the hybridization experiments – that the evidence was in the form of files that made connections to Mulder's father and other individuals who were involved with the Syndicate. (TXF: "Two Fathers")
With the Syndicate having developed the first successful alien/human hybrid (Cassandra Spender), the CSM argued that the group should hand Cassandra over to the aliens and allow colonization to begin but another Syndicate member recounted that Bill Mulder had opposed the idea of allowing colonization. The CSM responded by expressing his opinion that Bill Mulder had sacrificed his only daughter because he had known that the day would come when the Syndicate would be faced, as they now were, with the decision of whether to go ahead with allowing colonization or not.
Agent Mulder later held the CSM at gunpoint and objected to his use of innocent women, in the effort to create a human/alien hybrid, but the CSM merely laughed before explaining that Bill Mulder had also been against that aspect of the Project, until he had come to his senses and given Samantha Mulder up. Agent Mulder argued that his father hadn't given Samantha up but had been forced, by the CSM, to surrender her. Laughing, the CSM strongly objected to this account of what happened and then began to explain the truth of what had actually happened, recounting how Bill Mulder had originally objected to the Syndicate's plans before he had thought up the idea of creating a vaccine and had realized that the Syndicate as well as those close to them would survive to see the abducted return to them. The CSM believed that Agent Mulder, as his "father's son", would also realize this or die in vain as a result of the alien's decimation of the world.
After virtually all the Syndicate members were killed by the faceless alien rebels, the CSM showed his son, Special Agent Jeffrey Spender, the photograph of himself with Bill Mulder, which had been lying in Agent Spender's office. The CSM remarked that he hadn't seen the picture since Jeffrey Spender's birth and made light of the fact that the other man in the image was Bill Mulder, who the CSM described as "a good man, a friend of mine, who betrayed me in the end." Believing that Agent Spender had also betrayed him, the CSM admitted that he had come to the office hoping that his son might live to honor him and likened his hopes for his relationship with his son to the way in which Bill Mulder had been honored by his own son. The CSM then shot Agent Spender in the face and left the office, taking the picture of himself with Bill Mulder as he exited. (TXF: "One Son")
Later that year, Agent Mulder hallucinated once again that he was visited by Deep Throat and, when Mulder stated that he had thought Deep Throat had died for his own quest, the hallucinatory version of Deep Throat listed other individuals whose deaths Mulder had felt responsible for, including a man whom he had thought had been his father. (TXF: "The Sixth Extinction II: Amor Fati")
In 2000, when Agent Scully attempted to discover why Mulder felt compelled to search for his missing sister even years after her abduction, Scully was told by Agent Schoniger that Mulder's father had worked at a high level in the government and that the search for Samantha Mulder had been extensive but ultimately unfruitful. After Scully discovered proof that the person who had called off the search for Samantha was the Cigarette Smoking Man, Mulder regarded Scully's evidence as not exactly revelatory and reminded her that the CSM had been a friend of his father. However, Scully continued to suspect the CSM, reminding Mulder that he said he also believed the CSM was guilty of wrongdoing such as being the man who had killed Bill Mulder. (TXF: "Closure")
By or in May 2000, William Mulder's name as well as the years of his birth and death were carved onto a Mulder family headstone that was mounted in Raleigh, North Carolina – where Teena Mulder was buried in that year – and the tombstone was also emblazoned with Fox Mulder's details, either by Agent Mulder himself (as he was aware that he was terminally ill) or by someone who added the details to the stone in an effort to make it look like Agent Mulder had done so. (TXF: "Within") The headstone with the details of William Mulder and his family was transported to FBI Headquarters in 2000, not long after Agent Mulder was abducted, and had been returned to Raleigh by 2001 – at which time, a funeral was held in Agent Mulder's memory, as his deceased body had recently been found. (TXF: "Within", "DeadAlive") Immediately following this funeral, Scully told Skinner that Fox Mulder had been the last of his family, mentioning that his other family members, including his father, were now all gone.
After Agent Mulder was found to be miraculously alive – three months later – but remained in critical condition, Krycek claimed to AD Skinner, as part of several methods that Krycek deployed in an attempt to manipulate the Assistant Director, that he himself had a vaccine that Mulder's father had developed to fight the alien virus and that this vaccine could save Agent Mulder's life. Krycek did indeed have a vaccine but effectively destroyed it, upon learning that Skinner had not followed his instructions, and Agent Mulder was fully revived as, essentially, a result of Skinner's defiance of Krycek. (TXF: "DeadAlive")
- This is the only occasion in The X-Files when Bill Mulder's efforts to create a vaccine against the alien virus are said to have been successful. Prior to this, the Syndicate are established as having obtained a vaccine – from the Russian program to create such a vaccine – but being unsuccessful in developing their own vaccine.
When Krycek had his final encounter with Agent Mulder later in 2001, Krycek held Agent Mulder at gunpoint and Mulder dared Krycek to go ahead and kill him in the same way that – according to Agent Mulder – the assassin had killed his father. Moments later, however, Krycek was killed by AD Skinner.
During Mulder's trial in 2002, Jeffrey Spender presented a testimony wherein he recalled that Agent Mulder had been unaware of his father's reluctant inclusion in the Syndicate and that, when Agent Mulder had begun to learn of his father's connection to the Cigarette Smoking Man, Bill Mulder had been killed by Krycek, who had been sent by the CSM. Skinner asked if Bill Mulder had been killed because the CSM wished to silence him, but Jeffrey Spender did not directly answer the question, instead recalling that Mulder's father had lived his life in shame, not due to his involvement in the conspiracy but because he had made the decision to surrender his own eight-year-old daughter, Samantha. (TXF: "The Truth")
- 1936: Born
- 1948: Begins working with the CSM on the Syndicate's Project
- 1950s: Helps collect genetic data for Operation Paper Clip but objects upon realizing that the data is intended to be used for the creation of an alien/human hybrid
- 1952: Working at the State Department (with workmates such as the CSM and Alvin Kurtzweil), Mulder discovers that a government conspiracy transformed Edward Skur, George Gissing and Terrill Oberman into something inhuman but that Gissing and Oberman committed suicide and that Skur has been written off as a Communist who killed himself. After failing to save a doctor from Skur, Mulder warns Agent Dales of both Skur and the government conspiracy. Mulder subsequently helps the conspiracy members track Skur down, only to later let him go free.
- August 19, 1953: Is part of a group (including the CSM) who – in a Pearl Harbor hospital – question an irradiated survivor of the Zeus Faber about an encounter with the "black oil" virus
- 1962: May have been stationed in the military with the CSM
- October 30, 1962: May have received news that his son's first words were "J.F.K." and relayed this news to the CSM
- 1972/'73: Poses with the other Syndicate members outside the Strughold Mining Company, the repository of their genetic data
- 1973: Engages the CSM in an argument that is photographed and objects to the Syndicate's collaboration with the Aliens but is nevertheless forced to witness this arrangement take place, with the other Syndicate members sacrificing their own family members to the Aliens
- Circa October 1973: Buys a vacuum cleaner for his wife
- Circa November 27, 1973: Has the idea of developing a vaccine against the Alien "black oil" virus and consequently finally agrees to cooperate with the Syndicate's plans but his lateness in making this decision leads to his daughter's abduction and a search for her is called off by the CSM later that year, after which Mulder goes into a period of isolation; he divorces his wife, moves out of their family home, makes an agreement with the CSM to have limited contact with each other, and becomes estranged from his own son by November 1990
- 1995: Is fooled into believing that a female clone is his own daughter and rounds up the rest of the Mulder family – his son and ex-wife – but is later angered to hear that his son allowed the clone to die
- April 13, 1995: Is disturbed to learn from the CSM that his own son has come into possession of the classified MJ documents and starts to reveal his involvement in the Project to his son but – while trying to medicate himself – Alex Krycek appears behind him and he is mysteriously shot to death, dying in his son's arms moments later
- The X-Files
- "Colony" (Season 2)
- "End Game"
- "The Blessing Way" (Season 3; photographs)
- "Paper Clip" (photograph)
- "Apocrypha" (flashback)
- "Talitha Cumi" (appearance assumed by Jeremiah Smith)
- "Musings of a Cigarette Smoking Man" (Season 4; flashback(?))
- "Demons" (flashback(?))
- "Travelers" (Season 5; flashback)
- The X-Files Movie (photograph)
- "Roland" (Season 1)
- "Little Green Men" (Season 2)
- "Clyde Bruckman's Final Repose" (Season 3; implied)
- "Piper Maru"
- "Tunguska" (Season 4)
- "Paper Hearts"
- "Zero Sum"
- "Redux II" (Season 5)
- "Dreamland II" (Season 6)
- "The Sixth Extinction II: Amor Fati" (Season 7)
- "Within" (Season 8)
- Anachronism: Bill Mulder was depicted as a government agent in the season 5 episode "Travelers", which takes place in 1952. He is listed as being born in 1936, making him sixteen at the time.
- In recognition of the fact The X-Files was originally highly inspired by the television series The Night Stalker, Chris Carter considered casting actor Darren McGavin – who played newspaper reporter Carl Kolchak, the protagonist in The Night Stalker – as Mulder's father. However, schedules couldn't be worked out for this to happen. (The Truth Is Out There: The Official Guide to The X-Files, p. 10)
- William Mulder was most regularly played by Peter Donat. Young versions of the character were played by Dean Aylesworth – in "Musings of a Cigarette Smoking Man", "Demons" and "Travelers" – and by two uncredited actors, in "Apocrypha" and the picnic photograph that appears in The X-Files Movie.
- When casting this role, the production crew of The X-Files had to cast Peter Donat from a tape, as the actor was in Canada at the time but was not in the series' production base of Vancouver. In fact, writer Frank Spotnitz never met Peter Donat, as their schedules never intertwined, even though Spotnitz was on the set of Mulder's apartment about the same time when the crew was filming the scene of "End Game" (the first episode that Spotnitz wrote for The X-Files) in which Bill Mulder visits the apartment.
- Although the first season episode "Roland" includes a reference to Fox Mulder's father when Agent Mulder recounts his dream to Roland Fuller, Fox Mulder's sister was originally to have been the family member featured in the dream and was therefore included in the scripted version of Agent Mulder's description of the dream.
- For Bill Mulder's appearance in second season finale "Anasazi", the series' makeup department covered up injuries that Peter Donat had, as his face was badly bruised as a result of having been in a car accident in California. He was nevertheless in a lot of pain while portraying Bill Mulder in the episode.
- For the scene of "Anasazi" wherein Bill Mulder has a discussion with the Cigarette Smoking Man at Mulder's home in Martha's Vineyard, Peter Donat first met CSM actor William B. Davis only shortly before the scene was to be filmed.
- Even years after "Anasazi" was produced and aired, David Duchovny routinely left phone messages for Nicholas Lea in which Duchovny accused Lea of having killed his father, owing to the fact that the father of Duchovny's character (Agent Mulder) is implied as having been killed by Lea's character (Krycek) in the episode.
- Visual effects producer Mat Beck found that creating the effect of Deep Throat and William Mulder separately appearing to Agent Mulder, in "The Blessing Way", was extremely difficult as there were many visual elements to add and arrange.
- William B. Davis' favorite line of dialogue from the third season finale, "Talitha Cumi", involved the Cigarette Smoking Man referencing Bill Mulder, when the CSM tells Teena Mulder, "He was a good water-skier, your husband. Not as good as I was, but then... that could be said about so many things, couldn't it?" Davis was amused and aware that this reference to William Mulder additionally implied that the CSM was a lot better in bed than Mulder had been. The statement was also an inside joke, as – at the time the episode was produced – Davis was actually a championship-level water-skier in reality.
- For the two-parter that is comprised of the episodes "Two Fathers" and "One Son", the look of several young versions of Syndicate members – including William Mulder, as played by Peter Donat – was created using strategically applied highlights and shading, wrinkle-erasing pieces of adhesive tape and one or two prosthetic devices.
- In these episodes, William Mulder was originally to have appeared in more scenes set in the early 1970s than he does in the final version of the two-parter. The scenes – which were filmed before the decision was made to exclude them from the episodes – also included the CSM as well as Dr. Eugene Openshaw and involved the Syndicate members preparing to close their deal with the Colonists, unaware of the doom awaiting themselves.
- William Mulder is featured in a segment of archive footage in the episode "The Truth" – the finale of both The X-Files' television series and its ninth season. Taken entirely from "Anasazi", this footage first shows a shot of Bill Mulder sitting with the CSM and then a close-up shot of Mulder turning his head away from the CSM and blinking. Following two shots of Agent Mulder finding the alien-looking test subjects, another shot of William Mulder shows him being unknowingly watched by Krycek before a final shot features Agent Mulder opening his father's bathroom door to find his dying father on the floor. This segment of footage is shown during Jeffrey Spender's testimony in "The Truth".
|Members of the Mulder family|
|William Mulder •||Teena Mulder •||Samantha Mulder •||Fox Mulder •||William Scully III|