BOISE, Idaho (AP) — An Idaho man has been arrested in connection with the shooting death of a woman in California more than 50 years ago, authorities said.

DNA evidence led investigators to identify Michael Eugene Mullen, 75, as a suspect in the death of Nina “Nadine” Fischer in 1973, the Marin County Sheriff’s Office said. Mullen was arrested near Salmon, Idaho, on Wednesday, and he is being held in jail while awaiting extradition to California.

Mullen’s defense attorney, Dan Brown, did not immediately respond to voice and email messages left for him on Saturday.

Fischer lived in San Rafael, California, with her husband and young daughter when the 31-year-old was killed in November 1973, the Marin County Sheriff’s office said in a news release. Both Fischer and her husband were Swedish nationals, and they were preparing to move back to Sweden at the time.

Fischer’s husband found her body when he returned home from work. She had been sexually assaulted and shot three times, and her 2-year-old child was found unharmed in another room.

Law enforcement officials questioned some witnesses — including movers and an assessor who had been at the house that day — but the investigation turned up no leads and the case went cold, according to newspaper articles published after her death.

In 2021, the Marin County Sheriff’s Office sent the case to the California Department of Justice’s Familial Search Program. The program compares DNA from crime scenes to a DNA database in an effort to try to find relatives of a potential suspect. After several months, the DNA resulted in a possible lead, and after three more years of investigation Mullen was identified as the suspect, the sheriff’s office said.

The Marin County District Attorney’s office and sheriff’s office worked with the Idaho State Police and the Lemhi County Sheriff’s Office to arrest Mullen on suspicion of murder. He is being held in the Lemhi County jail.