Marilyn Monroe was tricked into killing herself by Bobby Kennedy.

So says Dr Jack Hattem, who, backed up by secret FBI files, says the Hollywood bombshell was somehow fooled into believing she would be revived in time as part of a plot involving Senator Robert Kennedy, the brother of JFK, who was gunned down 40 years ago this week.

Instead, Monroe, who staged many fake suicide attempts throughout her life to gain sympathy, was left to die by staff and friends. It’s all in Hattem’s new book Marilyn Monroe: Murder By Consent.

Certainly, Marilyn Monroe may have been dead for 46 years, but that doesn’t mean that people have stopped speculating about the circumstances of her death. We spoke to Dr Hattem and listened to some of his more compelling claims, including where Kennedy was on the night of Marilyn Monroe’s death and why the recently unearthed Marilyn Monroe sex tape might not be the only one knocking about.

This is turning out to be quite a big year for Marilyn Monroe. Not only has Lindsay Lohan aped her by getting naked and covering herself with a net curtain, but a Marilyn Monroe sex tape has also apparently been uncovered in recent months. So with sex dealt with, what about death?

While it was ruled to be suicide, theorists have long had their doubts about the way that Marilyn Monroe died – and thanks to a set of FBI records released 20 years ago that have been inexplicably ignored until recently, those doubts seem to have some substance.

According to Dr Jack Hattem’s book Marilyn Monroe: Murder By Consent, Monroe died because Robert Kennedy, along with Monroe’s close ‘friend’ and Hollywood actor Peter Lawford, convinced her to make another fake suicide attempt.

Caught between his family, who wanted to play down its relationship with Marilyn Monroe and the fact Monroe was threatening to shop a red diary containing ‘pillow talk’ between the pair and confidential secrets about the Cuban Missile Crisis if he ever left her, Robert Kennedy and Rat Pack member Lawford hatched a plan to visit Monroe on the day of her death. Hattem said:

“It is my guess that they had discussed with her, in no uncertain terms, that they needed for her to fake a suicide attempt. They guarantee she would be woken up, and that the fake suicide attempt would gain her so much sympathy from 20th Century Fox – who had fired her – that she would get her job back. But they threatened her somehow. She could be talked into things, because she wanted desperately to be cared about.”

At the time, Kennedy denied the visit, claiming he was in San Francisco. Which he might have got away with, except for the fact the FBI just happened to be busy tracking both Robert Kennedy and Marilyn Monroe at the same time. Hattem explained:

“The CIA had long considered Marilyn Monroe a threat to national security from the time she had married Arthur Miller, because they thought of him as a leftist. Then the FBI started listening in on her phone calls and tracking her – even to Mexico, where Bobby Kennedy had a fling with her. A private detective took an audio tape of Bobby Kennedy and Marilyn in an ‘affair’. The FBI was tracking Kennedy, their boss, all over the place and listening in on his conversations, possibly because Hoover wanted something on Kennedy – and he certainly got it, because as she was dying, they were listening in.”

Adding to the muddle is Marilyn Monroe’s housekeeper Eunice Murray, who found her face down on her bed, and her psychiatrist Ralph Greenson.

Apparently, Monroe fired Murray on the day of her death – which Hattem suggests is why she didn’t rush to try and revive Monroe; and was sleeping with Greenson – who allegedly gave Monroe an extra-large dose of barbiturates on top of what she already had been given.

What’s most interesting, though, is Dr Hattem’s story of the conversation between Bobby Kennedy and Peter Lawford at around 4am the following morning:

“In the FBI files, the FBI is recording Kennedy saying to Peter Lawford ‘Is she dead yet?’”

Throw in the fact that all of Marilyn Monroe’s phone message disappeared, to later be discovered in the chief of police’s private files, and that her red diary could not be found – Hattem’s guess is that Kennedy had a large hand in it. He said:

“I’m certain Robert Kennedy stole it when he came by her house after she was dead.”

But if Robert Kennedy’s involvement in Marilyn Monroe’s death is rooted in fact so firmly that there’s even an FBI file on it, why hasn’t more been made of it?

“I think the reason is that everybody already believes the Kennedys killed her.”