Senia Marie Mattson was last seen in the pre-dawn hours of July 3, 1983, at a cabin on the western shore of Carp Lake (also called Trout Lake) in Trout Lake Township, Michigan. Reports say she had been drinking heavily and left the cabin around 4 a.m., walking into the woods; she was never seen or heard from again.

At the time she vanished she reportedly wore a light blue sweatshirt, blue jeans, maroon sneakers, a gold wedding band and a gold watch. She had scars from mastectomies and a scar on her left upper arm from tattoo removal.

Extensive air and ground searches of the dense woods around Carp Lake found no trace; no personal effects or remains are publicly reported. The Michigan State Police are listed as the investigating agency. Did anyone who knew Senia or who spent time at Carp Lake in early July 1983 ever notice her or recall seeing someone matching her description that morning?