AUBURN — Lawyers for an Auburn man charged with murder in the 1993 rape and slaying of a former student at the University of Alaska Fairbanks campus filed several motions Monday to exclude DNA and firearm possession evidence from the defendant’s trial.

Monday’s motions followed a series of motions filed Nov. 25 by lead Maine lawyer James Howaniec in a Fairbanks, Alaska, court.

The motions filed last month seek to dismiss the case against Stephen H. Downs, 45, based on the argument that “a few spermatozoa molecules” are the only physical evidence linking Downs to the rape and killing of Sophie Sergie, 20, who was visiting a friend at the school in April 1993, when her body was discovered in a dormitory bathroom.

Investigators said Sergie had been shot in the back of the head with a .22-caliber gun, stabbed in both eyes, struck with a blunt instrument, gagged with a ligature and shocked with a stun gun.

Downs was a freshman at the school and living in the same dormitory at the time of the killing.

The case went cold for decades until last year, when DNA evidence from a commercial genealogical database helped police link Downs to the crime through an aunt.

Howaniec filed four motions Monday in the Alaska court, including motions to exclude all evidence of DNA, evidence of Downs’ possession of weapons, evidence or opinion testimony about the timeframe that DNA came into contact with Sergie and other miscellaneous evidentiary issues.

In the first of four motions filed Monday, Downs argues the state of Alaska has failed to provide a number of DNA discovery materials as of Monday, including reports related to DNA analysis and testing and professional background information about the people involved in conducting or reviewing DNA testing.

Downs’ lawyer wrote in the motion that the DNA evidence in the case is “completely unreliable.”

According to the motion to exclude DNA evidence, a lead investigator is quoted telling the FBI that 19 people, including students, had entered the bathtub area to see Sergie’s body — thereby contaminating the crime scene — before the investigator and his crew arrived.

The motion reads that in 1993, the original medical examiner, who is now believed to be deceased, had examined Sergie’s body, collected DNA samples and wrote a “very brief” report.

During a reexamination of the 1993 autopsy report years later by a forensic expert, that the “expert came up with a number of conclusions that were significantly contrary to the conclusions of the original medical examiner,” according to Downs’ lawyers.

In support of their request to exclude evidence of Downs’ possession of weapons, his lawyers said affidavits, grand jury proceedings and bail arguments claiming Downs owned a .22-caliber revolver in the second semester of his freshman year at UAF in April 1993 are “completely false.”

Although prosecutors have claimed the murder weapon was a .22-caliber handgun seized earlier this year from Downs’ home in Auburn, he and his lawyers said he bought the gun in Turner in 2016.

In their motions, Downs’ lawyers argue there is no evidence that any of his firearms or knives were connected in any way with Sergie’s death, and there is no evidence that Downs owned a “stun gun, a ligature or any sort of blunt force object that would have been used in the assault on (Sergie).”

“Furthermore, any evidence of (Downs’) connection to weapons is tenuous and irrelevant to the evidence in this case,” Downs’ lawyers wrote in their motion.

In another motion filed Monday, Downs’ lawyers argue that while the state of Alaska has produced “some level of evidence” that there may have been sexual contact between Downs and Sergie, there is “no evidence as to when such sexual contact may have occurred.”

The motion also points to a statement made by Randel MacPherron, a detective with the Alaska State Police, in an affidavit submitted to the court. That affidavit states, “DNA alone is not enough to prove Downs committed the murder, only that he had sexual intercourse with Sergie,” and that the DNA evidence could not indicate whether the intercourse was consensual or not.

In yet another motion, Downs’ lawyers requested miscellaneous evidence be excluded from the trial, including what Downs read, the music he preferred or his other interests at the time of the killing or since Sergie’s death. The motion also seeks to exclude information about Downs’ breakup with an former girlfriend.

Downs also requested in one of the motions that he be allowed to have a hearing to “establish the alternate suspects defense will be allowed to present at trial,” as the “state has systematically failed to properly investigate these suspects, despite shocking evidence pointing towards their guilt.”