DNA evidence has led California authorities to arrest a man linked to a cold homicide case that went unsolved for more than 50 years.

Michael Eugene Mullen, 75, was arrested for the murder of Nina "Nadine" Fischer, a Swedish national who was sexually assaulted and killed in her San Rafael, California, home while her husband was at work during the day in November 1973, according to the Marin County Sheriff''s Office.

Fischer's husband, Gunnar, discovered her naked body had multiple gunshot wounds, according to the AP and SFGate. In addition, the victim's hands were tied, and her mouth gagged.

Her 2-year-old was in the home with no injuries. The incident occurred amid the couple's plans to move back to Sweden. According to the reports, despite questioning movers and an assessor, the case went cold.

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New lead results in arrest

Decades later, in 2021, the investigation was revitalized. The Marin County Sheriff's Office investigations division transferred the case to the California Department of Justice’s Familial Search Program, and just months later, the agency provided a lead that prompted a three-year investigation.

Their findings led to Mullen's arrest for Fischer's murder on Wednesday, August 14. He was transported to the Lemhi County Jail in Idaho and is set to be extradited to California. Speaking to SFGate, Sgt. Adam Schermerhorn said that Fischer and Mullen didn't appear to know one another.

According to the Marin County Sheriff's Office, the case was solved using DNA. At the time, Mullen reportedly lived in Sonoma, which about about 27 miles from San Rafael.

"The Marin County Sheriff’s Office would like to thank the Idaho State Police, Lemhi County Sheriff’s Office, Marin County District Attorney’s Office, California Department of Justice, and Federal Bureau of Investigation for the countless investigative hours and perseverance to bring closure to this case," the sheriff's office said in a statement.

San Rafael is about 18 miles from San Francisco.

Taylor Ardrey is a news reporter for USA TODAY. You can reach her at [email protected].