SAN DIEGO (AP) - A 75-year-old Pennsylvana man pleaded not guilty Tuesday to strangling a young Southern California mother in 1969.

John Sipos entered the plea in San Diego County Superior Court and was ordered held on $3 million bail.

Prosecutors and police said DNA evidence and forensic genealogy led to his arrest in the half-century-old killing of Mary Scott.

Scott, 23, was living alone in an apartment in the North Park neighborhood of San Diego on Nov. 20, 1969 when someone kicked in her door, broke her jaw during a fight, raped and killed her, prosecutors said.

Scott, who was separated, left two young girls, who were living with her husband’s family at the time of her death.

Sipos was arrested this fall at his home in Schnecksville, near Allentown.

Sipos reportedly had recently gotten out of the Navy and was living in San Diego when Scott was killed.

Sipos wasn’t charged with rape because the statue of limitations expired but if convicted of Scott’s killing he could face a possible life sentence, the San Diego Union-Tribune reported.

After the hearing, Sipos’ attorney, Brooke LaFrance, said she argued for lower bail, noting that he had no criminal record, the Union-Tribune said.