Investigators have arrested an Idaho resident on suspicion of murdering a San Rafael woman in 1973, the Marin County Sheriff’s Office announced Thursday.

Michael Eugene Mullen, 75, was linked by DNA evidence to the case of Nina Fischer, who was slain at her home on Point San Pedro Road. Fischer was 31 years old.

Authorities booked Mullen into the Lemhi County jail in Idaho, where he awaits court proceedings for an extradition to California.

The victim’s husband, Gunnar Fischer, found her body after coming home in the evening from his office in San Francisco, authorities reported at the time. She had been bound, gagged and shot twice.

Investigators found no sign of forced entry into the home. The Fischers’ 2-year-old daughter was found unharmed and napping in another room.

The Fischers were Swedish nationals who had lived in the Bay Area for three years. They had plans to move into a San Francisco apartment.

Gunnar was an executive for Corona Industries International Corp. He attempted to call his wife several times on the day she was found dead.

Neighbors last saw Fischer in her yard, where she spoke with a moving crew that delivered a shipment container for her.

“The case was investigated but eventually, unfortunately, went cold, due to a lack of investigative leads,” the sheriff’s office stated Thursday.

In 2021, Marin County sheriff’s detectives submitted the case to the state Department of Justice’s familial search program to help find leads. Within a few months, state authorities gave them a lead, reviving the investigation.

Investigators used DNA evidence collected from the crime scene, sheriff’s Sgt. Adam Schermerhorn said. He said investigators know of no prior connection between Mullen and the victim.

The sheriff’s office credited the Idaho State Police, the Lemhi County Sheriff’s Office, the Marin County District Attorney’s Office, the California Department of Justice and the Federal Bureau of Investigation for assistance on the case.