Matheson was last seen in Barre, Vermont at 9:30 a.m. on September 30, 1993. He lived with his brother at the time of his disappearance. His brother said Matheson was upset over his mother's recent illness and he left driving his 1989 Toyota Corolla. He has never been heard from again. His car was later found abandoned and burned near Kankangamus Highway in the White Mount National Forest in Albany, New Hampshire. An extensive search of that area turned up no sign of Matheson. His case remains unsolved.