Marion Marcella Rosamond Thiessen, 52, was last seen in Elliot Lake, Ontario, on October 1, 1979. Her husband reported her missing in November 1979. At the time she was described as a Caucasian woman, 5 feet 4 inches, 165 pounds, heavy build, grey curly hair, brown eyes, wearing eyeglasses. She was last seen in a blue cotton short-sleeved dress, a blue synthetic raincoat, and brown leather low-heeled shoes, carrying a black leather purse. Distinctive surgical scars on her chest and pelvis from a hysterectomy were noted.

Marion had a history of going missing on multiple prior occasions and had lived in Vancouver, British Columbia, at some point. The next and final known contact came in 1984 when she reportedly reached out to an acquaintance; no further information about that contact is given and she has not been heard from since. Few other concrete details are available about her movements after October 1, 1979. If anyone knew Marion, saw her in Elliot Lake around that date, or has information about the 1984 contact, please come forward.