A 15-minute film clip of late movie legend Marilyn Monroe in a compromising position with an unknown man was sold to an anonymous businessman for $1.5 million (£760,000).
Rumours have persisted that the man in the video clip is assassinated US President John F Kennedy, who was allegedly having a sexual relationship with the Some Like It Hot star.
The film is a copy of a 1950s black-and-white 16-mm clip owned by the Federal Bureau of Investigation.
Memorabilia collector Keya Morgan said he recently arranged the sale of the film on behlaf of the son of a dead FBI informant to a wealthy Manhattan businessman who wants to protect Monroe's privacy.
Mr Morgan said: "The gentleman who bought it said out respect for Marilyn he's not going to make a joke of it and put it on the Internet and try to exploit her.
"That's not his intention and I would never get my name involved if that were to happen."
Mr Morgan is a well-known collector of memorabilia from the estates of Monroe and her ex-husband Joe DiMaggio.
He claims to be friends with Monroe's other two husbands, Jim Dougherty and Arthur Miller.
Monroe was found dead in 1962 and many conspiracy theorists believe she was murdered because of relationships with JFK and his brother Robert Kennedy.