Marcel appeared on radio, television and documentaries, and wrote a book called "The Roswell Legacy," all on the subject of his father, who was reportedly the first military officer at the scene of the crash.
Marcel Sr. was an Air Force intelligence officer sent to investigate the crash site in July 1947. Marcel Jr. claimed his father brought a piece of the debris home and woke him up in the night, saying the boy would never again see anything like it.
Just 10 at the time, Marcel Jr. claims he was most interested in a small beam with purple hieroglyphics.
He maintained his whole life that the Roswell wreckage was alien in nature, and not the weather balloon described in official reports.
Less than two months after making his last trip to Roswell to visit the wreckage site, Marcel was found dead in his home Saturday. He had been reading a book about UFOs. He is survived by his wife and eight children.