Missing Since: 1982-12-21 Location: Las Vegas, Nevada
Cowan was last seen in Las Vegas, Nevada on December 21, 1982. He left home, never returned and has never been heard from again. Little information is available in his case, but the prime suspect in Cowan’s disappearance is David Dale Morgan, a former business associate of his. A photograph of David is posted with this case summary. He is believed to be responsible not only for Cowan’s disappearance but for the disappearances of others: Gabriel Vincent, who had had an affair with David’s wife Marie and was blackmailing David when he disappeared in 1979; Marie herself, missing since 1980; and David’s girlfriend Diana Leone, missing since 2000. In 2007, David was arrested and charged with Vincent’s murder. The case was reopened after a witness told police he witnessed David murder Vincent and helped dispose of the body. The murder case against David was dropped in 2012, however, because the witness had died and prosecutors couldn’t prove David’s guilt without his testimony. Cowan, Marie and Leone’s cases remain unsolved and charges have been not filed against anyone in connection with their disappearances, but David is considered to be the prime suspect in their cases as well as Vincent’s. Investigating Agency Las Vegas Metropolitan Police Department 702-828-2907 Source Information Las Vegas Metropolitan Police Department NamUs The Las Vegas Sun The Las Vegas Review-Journal Updated 1 time since October 12, 2004. Last updated October 9, 2025; casefile added.