MINNEAPOLIS (AP) — A drifter’s conviction of murdering three American Indian women in Minneapolis in the 1980s should be thrown out because of newly discovered DNA evidence, the man’s attorneys argued in court documents filed Tuesday.

Lawyers for Billy Glaze contend in a petition filed in Hennepin County District Court that the DNA evidence proves his innocence and that he should be granted a new trial.

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Glaze, now 70, is serving three life sentences for the murders of Kathleen Bullman, Angeline Whitebird Sweet and Angela Green, in 1986 and 1987. The women were raped, killed and mutilated in similar ways, leading police to search for a serial killer.

Glaze wrote from prison to the Innocence Project, a group that uses DNA analysis to re-open criminal cases. Glaze, who was convicted in 1989, has always maintained his innocence.

The Innocence Project had three labs run DNA tests on dozens of pieces of evidence from the three Minneapolis crime scenes that led to Glaze’s conviction. It took years to get the results, but Glaze’s attorneys say the tests show there is no trace of DNA belonging to Glaze at any of the crime scenes.

“In a case like this where not only is it a violent homicide but there’s also a sexual assault involved, you would certainly expect to see some DNA from the perpetrator at the scene and we didn’t find any DNA from Billy Glaze,” Innocence Project lawyer Olga Akselrod said.

Instead, the group said tests showed the DNA profile of another man — a convicted rapist —at two of the three murder scenes.

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“You look at the evidence that they were able to present against Billy Glaze at the time of trial. It was the best they could come up with, with the tools they had available at the time,” said Julie Jonas, an attorney with the Innocence Project of Minnesota.

“If they would have had what they have now against this person who really did the crimes, he would have been the one who was arrested. He would have been the one on trial,” she said.

David Brown, chief criminal deputy for the Hennepin County Attorney’s office, said the evidence against Glaze was “very strong,” but the office will review the new claims and respond.

“There were eyewitness identifications. We had statements by him (Glaze) regarding his hatred of Native women and his desire to mutilate them. He had confessed to doing these three murders,” Brown told The Associated Press.

Glaze, who is serving his prison sentence in Delaware, was not made available for comment by his attorneys, who said he suffers from mental illness.

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