Mitchell was last seen in Anacortes, Washington on January 25, 1986. He and two friends, Keith Humenik and Anthony Beirnes, went out on the ocean in a homemade ten-foot white aluminum skiff. They were last seen near Fidalgo Island. It was supposed to be only a short trip, but none of them returned to shore or were ever heard from again. Searchers found one of the skiff's oars on the south side of Burrows Island, but this was the only trace of the missing boys that was ever located.