Joseph Edward Duncan the third

Duncan has a long history as a violent sexual predator. His first recorded sex crime occurred in 1978 in his hometown of Tacoma, Washington, when he was 15 years old. In that incident, he raped a nine-year-old boy at gunpoint. The following year, he was arrested driving a stolen car. He was sentenced as a juvenile and sent to Dyslin's Boys' ranch in Tacoma, where he told a therapist who was assigned to his case that he had bound and sexually assaulted six boys, according to a report by the Associated Press. He also told the therapist that he estimated that he had raped 13 younger boys by the time he was 16.

In 1980, also in Tacoma, Duncan stole a number of guns from a neighbor and then abducted a 14-year-old boy and sodomized him at gunpoint. Duncan was sentenced to 20 years in prison, but was released on parole in 1994 after serving 14 years. While out on parole, Duncan is known to have lived in several places in the Seattle area. He was arrested in 1996 for marijuana use and released on parole several weeks later with new restrictions. Authorities believe that during his parole, Duncan murdered Sammiejo White and Carmen Cubias in Seattle in 1996 and Anthony Martinez in Riverside County, California in 1997; however, both those cases went cold and were not tied to Duncan until after his arrest in the Groene case. Duncan was arrested in Kansas and returned to prison in 1997 after violating the terms of his parole. Duncan was released from prison on July 14, 2000 with time off for good behavior, and moved to Fargo, North Dakota

In March 2005, Duncan was charged with the July 3, 2004 molestation of two boys at a playground in Detroit Lakes, Minnesota. On April 5, 2005, he appeared before a Becker County judge, who set bail at US$15,000. A Fargo businessman with whom Duncan had become acquainted helped him post bail; however, Duncan skipped bail and disappeared. On June 1, 2005, a federal warrant was issued for Duncan's arrest on the charge of "unlawful flight to avoid prosecution.