Strassburger was last seen on his way home from work in Le Claire, Iowa at 12:15 a.m. on August 6, 1982. He never arrived home and has never been heard from again. His 1976 Oldsmobile was found abandoned in the eastbound lane on the Le Claire bridge over the Mississippi River on Interstate 80, about fifteen miles from his home, half an hour after he left work. Extensive searches of the river and the area around it turned up no sign of Strassburger.

Three years after Strassburger vanished, a witness in a court proceeding in another state claimed to know about a homicide connected to Strassburger's case. Authorities described the information as "extremely credible" and stated the witness knew information about Strassburger's disappearance that had never been publicly released. They were never able to verify the witness's account, however.

Strassburger was employed as a machinist at Rock Island Arsenal at the time of his disappearance. He lived with his parents in Davenport, Iowa. Investigators believe he was the victim of a homicide, but little information is available in his case.