MINNEAPOLIS (WCCO) — The Hennepin County Attorney was reviewing new evidence Wednesday that could clear a man convicted of serial killings in the 1980s.

The Innocence Project filed court papers Tuesday, attempting to free 70-year-old Billy Glaze. He was convicted of killing three Native American women in 1986 and 1987.

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At the time, prosecutors used circumstantial evidence to tie Glaze to the killings, but the Innocence Project says it now has DNA evidence linking another man to the murders.

When Glaze was arrested in 1987, it ended an intense investigation. Kathleen Bullman, Angelina Whitebird Sweet and Angela Green were raped, murdered and mutilated in similar ways, leading Minneapolis Police to search for a serial killer.

Glaze was convicted in 1989, and has been in prison ever since.

“They didn’t have the tools that we have today to be able to figure out that they actually did charge the wrong person,” said Ed Magarian of Dorsey and Whitney, one of the attorneys from the Innocence Project.

That group filed hundreds of pages in court, citing dozens of DNA tests that found nothing linked to Glaze.

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Semen found in one of the victims, however, was connected to a convicted rapist.

“This person, whose DNA it is, had sex with Angela Green right around the time she was killed,” Magarian said.

Documents show that same man’s DNA was also found on a cigarette butt from one of the other murder scenes.

“It draws a much stronger case against that person,” Magarian said, “than the non-existent case where there was no physical evidence, no biological evidence, against Billy Glaze.”

In response, the Hennepin County Attorney assigned two senior prosecutors to review the claims.

“Nothing we have seen so far has changed our opinion that Billy Glaze is the person who committed these sexual mutilations and murders,” said Assistant Hennepin County Attorney David Brown. “However, we will take a very careful look at the petition that’s been filed.”

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Glaze will turn 71 in July. He’s in prison in Delaware, and his lawyers say he’s in poor physical health.