<P> Mark Frasier Landon was adopted in 1956, aged 7, by the 20 - year - old actor Michael Landon . Mark's biological mother was Michael's then wife, Dodie Levy - Frasier . </P> <P> Mark Landon appeared in three movies, including the CBS television movie Us (1991), which was written and directed by Michael Landon shortly before his death in 1991 . It aired a few months after Michael Landon died . Mark also had a small role as a Navy SEAL in the 1997 movie Goodbye America . </P> <P> Mark Landon was found dead at his West Hollywood home in the 1300 block of North Sweetzer Avenue around noon on May 11, 2009, at age 60 . He was interred at the Hillside Memorial Park Cemetery in Culver City, California, in the same room as his father . </P> <P> Hollywood sheriff's investigators stated that there was no suspicion of foul play . </P>

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