Frank Sinatra Died Believing This Rumor About Marilyn Monroe, New Book Says
Benjamin Ward
Updated on February 23, 2026
A new book is making a big claim about friends and entertainment icons Frank Sinatra and Marilyn Monroe. Sinatra's manager and friend Tony Oppedisano is releasing his memoir, Sinatra and Me: In the Wee Small Hours, and an excerpt published by People reveals that Sinatra believed a rumor about Monroe's death until he himself died in 1998.
While Monroe's cause of death was officially established as a barbiturate overdose, apparently Sinatra believed that something more sinister happened to the actor. Read on to see what Oppedisano has to say about that theory and their relationship now.
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Monroe died tragically when she was at the height of her fame.
Monroe was found dead in her home on Aug. 5, 1962 at age 36. It was determined that she had died of a barbiturate overdose the previous evening. According to History, Los Angeles police said at the time that her death was "caused by a self-administered overdose of sedative drugs."
Sinatra didn't believe it was accidental, according to the new book.
Oppedisano claims that Sinatra believed that Monroe was actually killed by someone. "Frank believed she was murdered, and he never got over it," Oppedisano writes in the excerpt.
According to Oppedisano, Monroe had reunited with her ex-husband Joe DiMaggio and was scheduled to give a press conference to reveal that they'd gotten back together. But, it was rumored that Monroe was also going to speak about her alleged affairs with John F. Kennedy and Robert F. Kennedy at that press conference. Oppedisano writes, "Frank said she'd never have spilled about the Kennedys because she still had feelings for [Jack]." The writer also claims that Monroe had talked about her relationships with both Kennedy men with Sinatra. "Marilyn told Frank she didn't understand why they'd shut her out completely" after she stopped being intimate with them, the book reads.
Sinatra thought she was killed because of the press conference rumor.
Oppedisano writes that "Frank believed if the press conference hadn't been announced, she would have lived a lot longer." That's because he thought that Monroe was killed to silence her about the Kennedys. Supposedly, people close to Sinatra told him about this conspiracy theory. They told Sinatra that Monroe had "been murdered with a Nembutal suppository and Robert Kennedy or the Mob was involved."
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Conspiracy theories about Monroe's death live on.
Conspiracy theories about Monroe's death persist to this day with requests having been made over the years for the case to be reexamined. In 1982, the Los Angeles District Attorney's office concluded that a criminal investigation wasn't warranted, and in 1985, a grand jury determined that an inquiry into the actor's death didn't need to be reopened. Just last year a new series called Cold Case: History, which would delve into the conspiracy theories surrounding Monroe's death, was announced.
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Lia Beck Lia Beck is a writer living in Richmond, Virginia. In addition to Best Life, she has written for Refinery29, Bustle, Hello Giggles, InStyle, and more.Read moreFiled UnderCelebrities • Entertainment • NewsRead This NextThe Most Dramatic Feuds in Hollywood History
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