By Erin McPike, CNN
The claims are hard to substantiate, because the recordings, if they existed, have been lost. If true, though, CNN's Erin McPike reports the revelations could shed light on rumored relationship between Marilyn Monroe and JFK.
There are intimate details of a reported relationship between a president, his brother, and a Hollywood sex symbol.
Eleven boxes of files Hollywood spy/private investigator Fred Otash socked away in a storage unit in the San Fernando Valley were reviewed by The Hollywood Reporter.
"This was someone who had wire taps all over town, was listening to the biggest stars in an era when some of these revelations would be published in magazines," said Matt Belloni, executive editor of The Hollywood Reporter. "Otash claimed that he had recordings of JFK having sex with Marilyn Monroe. He spoke about this as if it was a common knowledge thing."
Otash worked for members of Hollywood's elite to dig up dirt on their enemies.
In notes he left behind before his death, reviewed by The Hollywood Reporter, Otash provides salacious details of the long-rumored affairs between Marilyn Monroe and both President John F. Kennedy and his brother, Robert Kennedy. He claims he listened to Marilyn Monroe having sex with John F. Kennedy.
And in the hours before her death, Otash says Monroe had a blow-out fight with Bobby Kennedy over their relationship. He claims Monroe complained she was being passed around "like a piece of meat."
Otash claims he heard Bobby Kennedy trying to quiet Monroe down with a pillow, so neighbors wouldn't hear her shouting, but the audio tapes his notes are based on have since disappeared.
"Some of these files that we reviewed contain elements that are not 100-percent verifiable. They are his recollections and his recollections to his daughter, so what he said and what is actual truth is not necessarily the same," said Belloni.
Otash was part of the LAPD until 1955 after a falling out with the police chief, so he became gumshoe to the stars.
Otash disguised a surveillance van as a TV repair truck. The real-life gumshoe helped inspire the fictional detective Jack Nicholson portrayed in the film noir classic, Chinatown.
"He was someone who moved naturally moved in Hollywood circles and also kind of in the gray zone between the police, the mob, the private investigators who made Hollywood in the 1950 such an interesting place," said John Buntin, author of "L.A. Noir."
Otash's daughter says she released the new information to The Hollywood Reporter, in part, to defend her father's reputation.