Sjoberg was serving as a United States Navy hull technician third class in 1996. He was last seen aboard the USS Harper's Ferry (LSD-49) at approximately 11:00 p. m. on October 18, 1996. The ship was reportedly passing between the Hawaiian islands of Kauai and Niihau at the time, coming as close as 2000 yards from shore at one point during the evening. Sjoberg disappeared from the ship and has never been heard from again. He is originally from St. Louis County, Minnesota.