Joel Matthew Thompson, 29, made a final known contact on August 31, 1999, when he called his father from St. Louis, Missouri. He said he was visiting friends and finishing preparations for a long hiking trip to the Portland, Oregon area before starting southbound on the Pacific Crest Trail, and expected not to be in touch for a couple of months. That phone call is the last confirmed sign anyone had of him.

At the time he disappeared Joel was described as a white male, between 5 feet 7 inches and 5 feet 10 inches, 170–180 pounds, with brown balding hair, blue eyes, and a brown beard and mustache. He was believed to be wearing size 32–34 jeans and brown hiking boots and carrying a large 50-pound backpack, a pocket knife, a disposable lighter, and a disposable camera. His father filed a missing persons report after the expected two months passed with no contact.

Law enforcement in Missouri, New York, and Oregon has investigated, but no trace of Joel has ever been found, no activity on his accounts has been identified, and the circumstances after that St. Louis call remain unexplained. If anyone knew Joel, saw him in late August 1999, or has information about his planned travel route, please come forward.