 Duncan's arrest led the FBI to launch a nationwide review of unsolved missing child cases.He was implicated as a possible suspect in several crimes that occurred between 1994 and 1997, when he was on parole, and between 2000 and 2005, when he was free from prison.Although he was cleared as a suspect in some cases, authorities in California and Washington had enough evidence to believe Duncan had committed unsolved murders in their jurisdictions.