On the afternoon of July 29, 1980, 44-year-old Francis Joseph Wisnovsky entered Lost Creek Lake in Trail, southern Oregon, as part of a diving operation to work on dock cables. Employed by the U.S. Army Corps of Engineers and also the owner-operator of Valley View Vineyard, he submerged at about 3:15 p.m. and never resurfaced.

Search efforts were extensive and prolonged: human divers and remote-controlled submarines were deployed to scour the lake to an estimated depth of about 150 feet, but no trace of Mr. Wisnovsky was ever found and his body was not recovered. The investigation concluded he was lost in the lake that day, but without a recovery the precise circumstances of his final moments remain unknown.

Did anyone who worked on the Corps diving teams or at Valley View Vineyard know details that could shed light on what happened that afternoon?