Welter was last seen in Ocean Springs, Mississippi in early January, 1986. He disappeared a day or two after he was arrested for drunk driving after having a minor accident on New Years' Day. He lived in Jefferson Davis Apartments at the time, and was a staff sergeant at Keesler Air Force Base. He was on leave when he disappeared and was scheduled to return to duty on January 6, but never arrived. The Air Force listed him as absent without leave (AWOL) on January 8. Welter's court date for the DUI charge was on January 15; he never showed up. He left behind his checkbook, savings book, passport and other personal belongings.

There has been no activity on Welter's Social Security number since January 1986. Private investigators hired by his family believe he may have taken another name and moved to Shreveport, Louisiana with a girlfriend, but this has not been confirmed. Welter, one of ten children, grew up in Illinois and attended Grant High School and Lake County College, where he was a champion athlete. He was declared legally dead in 2002. His case remains unsolved.