Margaret Blackbird was 21 and living on Big Island Lake Cree Nation when she vanished from Loon Lake, Saskatchewan, in 1951. She left behind two young children, including a six-month-old son, Billy. Accounts from relatives differ about why she left: one said she told her father she was going to a tuberculosis sanatorium, another said she left because she was angry with her husband. No photograph of her is known to exist.

At the time she disappeared she was described as 5 feet 3 inches tall, about 150 pounds, with black hair and brown eyes. Over the years scattered, unconfirmed sightings and rumors placed her in places such as Lethbridge, Alberta, and possibly British Columbia, while one tragic rumor suggested she might have died in a car crash in Edmonton. None of those leads was confirmed and police have not located a definitive trace.

Her son was raised by his maternal grandfather and did not reconnect with his sister Marlene until he was 13. The investigation remains open with the F Division RCMP Historical Case Unit.