MINNEAPOLIS (AP) — Minneapolis police have tracked down a suspect in a homicide that happened 32 years with some help from advances in DNA evidence and scrapings from under the victim's fingernails, police said Wednesday.
Medical technician Mary Steinhart, 22, was found stabbed to death in her Minneapolis apartment on Nov. 25, 1980. Steinhart was sexually assaulted and stabbed more than 25 times, Minnesota Public Radio News reported. Her sister found Steinhart's body.
Police arrested the 57-year-old suspect in Kansas last week.
Minneapolis Police Capt. Amelia Huffman said new DNA technology helped crack the case.
"In this case, particularly with it being it so old, the nature of the physical evidence is really key," Huffman said. "In this particular case, we have multiple sources of DNA profile from the suspect, including from beneath the victim's fingernails, which is really critical evidence, because boy, that's tough to explain away."
The suspect was once a caretaker at the victim's Uptown apartment building, but didn't hold that job at the time of the homicide. Investigators don't believe Steinhart knew him. There was no sign that her basement apartment had been broken into.
Detectives used fingernail scrapings and other evidence to find a match in the national DNA database, the Star Tribune reported. The suspect has a criminal history of burglary and a sexual assault in California. Police credit advances in DNA technology and a grant from the National Institute of Justice for finally making an arrest.
The investigation into Steinhart's killing went cold 30 years ago, Minneapolis Police Lt. Robert Zimmerman said.
"At the scene they collected the sheets, they collected blood evidence. They did a lot considering the standards of 1980," Zimmerman said. "It just wasn't useful 30 years ago."
Police said the man wasn't a suspect at the time of Steinhart's killing.
In 2011, police traveled to the sheriff's office in Johnson County, Kansas, to interview the man. He denied involvement in Steinhart's death, police said. But a year and a half later, police assembled their case.
Investigators said rape was the motive for the killing.
Copyright 2012 The Associated Press.