FORT COLLINS, Colo. -- Did prosecutors wrongly convict a 15-year-old boy in a slaying and ignore as a possible suspect a doctor whose upstairs overlooked the crime scene?

Attorneys for Tim Masters, convicted of first-degree murder in the 1987 slaying of Peggy Hettrick in Fort Collins, have alleged Larimer County prosecutors mishandled skin-cell DNA found on Hettrick's clothing and are asking for a retrial.

Masters was convicted in 1999 on a circumstantial case that included violent pictures he had drawn and the fact that he lived 100 feet from where Hettrick's body was found and had seen the body but didn't report it.

In a hearing that began Thursday, prosecutors said a retrial hinges on whether Dr. Richard Hammond, an eye doctor, was a viable suspect during the investigation. Defense attorneys want to focus on possible mishandling of the DNA evidence and want to leave the question of whether Hammond was a suspect for a retrial.

Hammond committed suicide in a Denver hotel in 1995. He was charged after police found an elaborate videotaping system in his home, and hundreds of videotapes of women using his bathroom, some showing extreme close-ups of their genitals. They also found $10,000 worth of pornography in his home.

Adams County prosecutor Mike Goodbee, who was appointed a special prosecutor in the case, said Hammond was never considered a suspect. In documents filed this week, Goodbee described Hammond as a bookish father who read to his children. On Feb. 11, 1987, when Hettrick was slain, prosecutors said Hammond was home with his wife.

Defense lawyers point to Hammond's fascination with women's genitalia and the fact that Hettrick's killer removed parts of her genitals. Some of the wounds on Hettrick's body originally were described by the county's medical examiner as "surgical" in nature. Later that was changed to wounds of "mutilation" that could have been done by anyone with a knife and a desire.

"This was a voyeuristic crime," said attorney David Wymore. "Someone wanted to look at and obtain her most private parts."

Police never looked at all the videotapes to see if Hettrick was pictured. They burned the evidence following Hammond's suicide.

Rebecca Hammond, Hammond's wife, told police that her husband primarily worked with lasers and that she did not believe he had ever had a scalpel in the home. She also said that about a year after the slaying police wanted to use the upstairs of their home to stake out the crime scene in case the killer returned to memorialize the death.

The hearing was expected to continue Friday.

"I want the courts to undo what they did to me," he told The Denver Post Wednesday night in an interview from the Larimer County jail. He stressed that he wants a new trial so he can be cleared "once and for all."