ST. JOHNSBURY, Vt. (AP) – A man suspected in the disappearance of a Vermont collegian who turned up dead last week denied having anything to do with it when interviewed by police, according to an affidavit filed Monday.

Police, meanwhile, said for the first time that 21-year-old Michelle Gardner-Quinn was the victim of a homicide. But they would release no other findings from the autopsy conducted Saturday.

“The cause of death will be listed as soon as test results from the medical examiner and additional information from the investigation becomes available,” police Lt. Kathleen Stubbing said late Monday.

In the affidavit, Brian L. Rooney, 36, told police he walked up Main Street in Burlington with the woman at about 2 a.m. on Oct. 7 but parted ways with her.

“He advised he separated from Gardner-Quinn at that point and he never saw her again. Rooney denied having any knowledge or involvement in Gardner-Quinn’s disappearance,” according to the affidavit by Detective James Claremont of the Vermont State Police, which was released just before a court appearance in which Rooney pleaded not guilty to sex charges unrelated to Gardner-Quinn.

Her body was found Friday at the top of a gorge in Richmond, about 15 miles east of the University of Vermont campus, where she was a senior.

Rooney, who was arrested Friday and charged with sexual assault and lewd or lascivious conduct with a child, has been named by Burlington police as a suspect in Gardner-Quinn’s disappearance but he has not been charged in it.

Monday’s court appearance focused primarily on the sex charges, which were filed based on information police said came to light as they investigated the disappearance.

In the affidavit, filed in Vermont District Court in St. Johnsbury, 80 miles east of Burlington, the image that emerges of Rooney is one of sexual predator who – on several different occasions – used chemical-soaked rags or other substances to render his alleged victims unconscious and unable to resist.

It said Rooney molested a girl in 1996 and 1998, when she was 12 and 14, respectively, and that he made advances against the girl’s sister.

Rooney is charged with lewd and lascivious conduct with a child for allegedly rubbing her through her panties in 1996 while in St. Johnsbury. A sexual assault charge was filed against him for allegedly drugging the girl in 1998 and having sex with her at his home in East Concord.

Lawyer David Sleigh entered a not guilty plea on Rooney’s behalf in District Court as Rooney, dressed in blue jeans, a sport shirt and tennis sneakers, sat silently at Sleigh’s side, his wrists cuffed and his legs shackled.

He made no comments, other than inaudible asides to his lawyers.

Assistant Attorney General Matthew Levine asked for $250,000 bail and Sleigh argued for $50,000. Judge Kathleen Manley imposed $150,000 and a list of conditions on Rooney’s release if he’s able to make bail.

Sleigh unsuccessfully asked that the charges be thrown out because, he said, there was insufficient probable cause to support them. He also questioned why charges that are a decade old were filed now that Rooney was under investigation in Burlington.

Sleigh described the sex charges as a “peremptory strike” by police investigating Gardner-Quinn’s disappearance, and argued for low bail, saying Rooney’s family ties were enough to discourage him from fleeing Vermont.

“Evidently, (the charges) weren’t of enough concern for anyone to bring forward, but they’re convenient at this point,” he said outside court.

Levine denied Sleigh’s contention, saying the charges resulted from legitimate information that came out during the probe of Gardner-Quinn’s disappearance and that there was enough substance to the victim’s allegations to warrant probable cause.

“We have an individual who was preying upon younger and weaker victims,” Levine told the judge.

Manley said Rooney’s risk of flight rose once Gardner-Quinn’s body was found and he was identified as a suspect, calling him a significant risk given the fact that he could face up to 35 years in prison if convicted on the sex charges.

The affidavit also included details of a temporary restraining order Rooney’s ex-wife obtained against him in 2000.

In the affidavit, the ex-wife – identified only as RB and who was only married to Rooney for six months – said she “left Rooney because she was afraid of him. Rooney drugged her many times so he could rape her.”

Rooney also threatened to kill his ex-wife on at least one occasion, according to the affidavit. “You will think I am funny when I kill you,” the woman was quoted as saying in the affidavit. “If you keep this up, I will bash your head in,” he told her, the affidavit said.

He also threatened that if she ever left and took their daughter it would be “your last mistake.”

Asked if Rooney would be able to make bail, Sleigh said he didn’t know. He declined comment about whether he had spoken to Rooney about Gardner-Quinn’s disappearance, and when asked if police had evidence Rooney was involved in it, Sleigh said: “You guys have more information about that than I do.”

AP-ES-10-16-06 1728EDT