Gary Mathias is the only one of the five men whose remains have never been found, despite searches of the area around the Forest Service trailer and the surrounding wilderness. Three of the other four men's remains were found relatively close to the trailer — Madruga and Sterling in late June 1978 in the nearby area, Huett's partial remains later. Mathias had the most significant mental health history of the group. Construct two competing hypotheses for Mathias's absence from the physical record, assess the evidentiary weight of each, and identify what single piece of new evidence would most definitively distinguish between them.