Case Details:Rudolph David Fantin, 38, of Sweetwater County, Wyoming, was last seen on August 11, 1991, in the area of Flaming Gorge Reservoir in Sweetwater County. Fantin is described as a white male, approximately 5 feet 7 inches tall (range 5'6"–5'8"), 175–185 pounds, with brown hair and blue eyes, and a tattoo on his right arm. Few details about the circumstances of his disappearance have been made public. Investigators have long theorized that Fantin may have fallen into the reservoir, though this has never been confirmed.

The case is investigated by the Sweetwater County Sheriff's Office (agency case #91-1922), with the Wyoming Division of Criminal Investigation assisting as the statewide clearinghouse for Wyoming missing-person cases. Fantin's case remains one of several long-unsolved missing-person cases originating in Sweetwater County. In November 2023, a hunter's discovery of a human skull in the Red Desert near Wamsutter — outside the Flaming Gorge area — prompted renewed regional attention to the county's unresolved disappearances, though authorities have not linked that discovery to Fantin. His case is catalogued in the NamUs national database (NamUs #MP117802) and the Wyoming DCI missing-persons list. Anyone with information is asked to contact the Sweetwater County Sheriff's Office or the Wyoming Division of Criminal Investigation. Case Number 91-1922.