Campbell was last seen in Anaheim, California on April 16, 1982. Police investigating his disappearance learned that he had met with two men, planning to fly to Fargo ND. Instead the plane went west, over the Pacific ocean. One of the men was arrested after it was discovered that he had Campbell's vehicle and was in the process of stripping it, and selling the parts. The men were tried and convicted of Campbell's murder. Authorities speculate that Campbell was thrown from the plane near Catalina Island. Campbell's remains have never been recovered.