Donald Kenneth Shelenberger was 35 when he disappeared in Pima County, Arizona, in the summer of 1994. On July 3 he arranged a hiking trip with a friend to Mount Lemmon; that call was the last known contact. After that day all contact stopped and it is unclear whether he ever met the friend or reached the mountain.

Shelenberger is described as a white male, brown hair, blue eyes, 5 feet 11 inches, about 160 pounds. Investigators report very few leads: no witnesses, no belongings found, and scarce details about his day. The Pima County Sheriff’s Department classifies him as an endangered missing person and keeps the case open.

If anyone remembers seeing Donald around Tucson or Mount Lemmon in early July 1994, or has information about his plans that day, please come forward.