Sadler moved to Guatemala City in 1984. He continued to write and publish his "Casca" books, produced a never-released self-defense video, and provided free medical treatment in rural villages. On September 7, 1988, Sadler was shot in the head while sitting in a cab in Guatemala City. Witnesses said he accidentally shot himself, but his friends and family believed he was shot by a robber or an assassin. He was flown to the United States by friends in a private jet paid for by "Soldier of Fortune" magazine publisher Bob Brown.