Karen O’Donoghue was 25 when she vanished from Springfield, Massachusetts, on July 2, 1969. She was about 5 feet 8 inches tall, 125–135 pounds, with strawberry‑blonde hair and blue eyes. Distinctive scars include a skin graft on one finger and a scar on her abdomen from the graft site. She had been engaged to be married and some reports from the time say investigators thought she might have voluntarily left her fiancé, but beyond that she simply disappeared with no confirmed sightings or leads.

Her case is filed as NamUs MP10038 and Springfield Police Department case number 12‑7355‑OF; dental records and DNA are recorded in her file. In November 2018 serial killer Samuel Little confessed to killing a young white woman he called the Scandinavian Girl in or around Homestead, Florida, circa 1970–71, and investigators later noted details from that confession that match Karen’s Air Force nursing background, substance struggles, and menstrual irregularities. Karen’s body has never been found or identified, and there has been no official resolution.