Dietz was last seen at her residence on Lantern Lane in Selbyville, Delaware at 3:30 a.m. on October 14, 1997. She was waiting for the morning newspaper at the time. She has never been heard from again. Her son reported her missing.

Foul play is not suspected in Dietz's disappearance. She was often seen in a disoriented state, sometimes digging through a dumpster behind her home. Around the time of her disappearance, a trash collector saw the empty dumpster with a door open at the side. Operating on the theory that Dietz was accidentally taken to a landfill after getting stuck in the dumpster, authorities searched the landfill. No trace of her was located and her case remains unsolved.