Mason was last seen on June 20, 2006. He and his wife were camping at a Dungeness/Forks U.S. Forest Service campground in the Olympic National Forest near Sequim, Washington when they got into an argument and his wife left the campsite. Mason went to a friend's house the next day and asked the person to give his vehicle and his wife's purse back to her. The friend drove him back to the campground and left him there. He has never been heard from again. He wasn't reported missing until June 29. A two-day search of the forest turned up no sign of him, only a cache of food.

Mason is an experienced camper and fisherman who knows the area well and had camped there for extended periods before. He was employed as a handyman at the Veterans of Foreign Wars post in Sequim at the time of his disappearance. His family believes he is deceased.