Bobby Kennedy really WAS with Marilyn Monroe the night she died, says bombshell book that reveals their final conversation. And here are the explosive things she told him…

With each passing year, the questions become louder and more urgent: What role did John F. Kennedy and his brother Robert play in the tragic death of Marilyn Monroe?

According to Marilyn’s second husband, New York Yankee legend Joe DiMaggio, this was a significant event. He banned the brothers from her funeral.

“That whole group of Kennedys were woman killers, and they always got away with it,” he is said to have said years later.

But that may not last much longer.

According to an explosive new book, which claims to provide evidence that Monroe had a heated argument with then-US Attorney General Robert F. Kennedy in the hours leading up to her death – and suggests he even drugged the actress to silence her.

Based on previously unpublished notes and transcripts of her final, allegedly wiretapped conversations, The Fixer offers a dark glimpse into the private world and seedy morals of the Kennedy brothers and the seedy celebrity circle around them, which included Frank Sinatra and her friend Peter Lawford.

The authors suggest that on the day she died, Marilyn, aged 36, made threats to Robert F. Kennedy – her lover – and bitterly accused him of abandoning her while she underwent abortion surgery to have their child.

To support their case, they turned to the investigative files of a police officer turned private investigator named Fred Otash.

Otash, known as “Dreamland’s ultimate fixer,” is said to have placed listening devices in Marilyn’s home in the weeks before her death.

The reason for the surveillance? The book doesn’t make it clear.

But the original tapes – if they existed – are believed to have disappeared shortly after Marilyn was found dead on August 5, 1962, of a fatal barbiturate overdose.

Authors Josh Young and Manfred Westphal claim they’ve found the next best thing: Otash’s personal notes and recordings describing what he found on his secret tapes.

The story begins on August 4, when a drunken Peter Lawford knocks on Otash’s door and says, “I think Marilyn’s dead.”

The detective immediately went to work “putting the pieces together” and sent a colleague named Reed Wilson to collect evidence from Marilyn’s home. He then listened to the secret tapes.

Otash’s notes show that RFK had flown from San Francisco to Los Angeles earlier that day at the instigation of Lawford, who was also Kennedy’s brother-in-law and had called Robert to say he was concerned about Marilyn’s mental state.

When Kennedy first arrived at her Brentwood home, Marilyn was distraught, Otash writes. As he reportedly notes in brutally direct language, “He fucked her about 11 o’clock that morning and then he left.”

RFK returned later that same day, this time with Lawford. But Marilyn was upset and yelled at him, “like there was no tomorrow.”

“On the recording that Reed Wilson and I heard, there was a serious problem,” Otash says.

She had made some threatening statements against [RFK] that he had made many promises and commitments to her.’

As Lawford and RFK tried to calm her down, Marilyn screamed, “Where were you when I had to abort your child, you worthless son of a bitch.”

The screaming became louder until RFK or Peter “grabbed a pillow” and “calmed her down on the bed” until “there was no more screaming.”

“Maybe he gave her something,” the detective suggests. “Or Peter gave her something.”

Robert Kennedy then allegedly left Marilyn’s house around 5:30 p.m. and told Lawford, “I’m getting out of here as fast as I can.”

Lawford asked Marilyn if she wanted to go out to dinner with him, to which she replied, “I don’t feel well. I don’t feel like it. I want to go to sleep. It’s been a bad few days for me.”

She called Lawford twice more later that night, repeatedly trying to locate Robert’s brother JFK, before calling Lawford again and saying, “Say goodbye to Pat. Say goodbye to the President, and say goodbye to yourself, because you’re a nice guy.”

Marilyn then dropped the (wiretapped) phone, according to Otash’s notes. She was found dead hours later.

The Fixer’s revelations follow Maureen Callahan’s exclusive series ‘Ask Not: The Kennedys and the Women They Destroyed’ on DailyMail.com, which exposed the “incestuous sexual competition” between JFK and his brother RFK over Marilyn.

Callahan, a columnist for the Mail, suggests that Marilyn fell in love with both men after she first met JFK at a Hollywood party in 1954 and was subsequently introduced to Robert.

Both brothers had affairs with Marilyn, Callahan says – affairs that overlapped.

Even on the night she sang “Happy Birthday” to JFK at Madison Square Garden in May 1962, Marilyn had slept with RFK in her dressing room.

Later that evening, Marilyn was captured in the only known photograph of her with the Kennedy brothers – the men who, Callahan says, bear a heavy responsibility for her fate.