Marilyn Monroe’s death on August 4, 1962 was not a suicide but a murder orchestrated by Bobby Kennedy to silence her as she was about to reveal all the dirty Kennedy family secrets she kept logged in a little red diary. And Bobby did not act alone. He had co-conspirators in her murder - his brother-in-law, actor Peter Lawford, and Marilyn’s psychiatrist, Dr. Ralph Greenson who gave the star a fatal injection of pentobarbital to the heart. Those are the explosive allegations detailed in a blockbuster new book by writers Jay Margolis, a long-time investigative reporter and Monroe expert, and Richard Buskin, a New York Times bestselling author of 30 non- fiction books. The volume - The Murder of Marilyn Monroe: Case Closed - claims to blow the lid off the world’s most notorious and talked-about celebrity death through eyewitness testimony and interviews,  MailOnline can exclusively reveal.‘Bobby Kennedy was determined to shut her up, regardless of the consequences’, Peter Lawford later revealed, according to the authors, feeling wracked with guilt over the star’s murder. ‘It was the craziest thing he ever did – and I was crazy enough to let it happen’.It was a murder allegedly witnessed by ambulance attendant James C. Hall, who arrived at the film star's home and saw Monroe’s psychiatrist Dr. Greenson inject Marilyn directly into her heart with undiluted pentobarbital, brutally breaking a rib with the needle. He was set up by Bobby to ‘take care’ of Marilyn.  Bobby Kennedy got involved in a messy sexual affair with Marilyn in the summer of 1962 when he was sent out to Los Angeles by his brother Jack to convince the screen goddess to stop calling the President at the White House. The President was not going to divorce Jackie and marry her. But Bobby fell under her spell and slipped into the bedroom with Marilyn.‘It wasn’t Bobby’s intention, but that evening they became lovers and spent the night in our guest bedroom’, Peter Lawford later revealed.The Kennedy helicopter always landed down on the beach in front of Lawford’s Santa Monica’s Gold Coast home in the Palisades area of Los Angeles. Jack Kennedy had spent so much time there having extramarital affairs with starlets and movie queens, it was dubbed the Western branch of the White House. Now it was Bobby’s turn.‘Almost immediately the affair got very heavy, and they began seeing a lot of each other,'  Lawford said. Marilyn shifted her attentions to Bobby and started calling the Department of Justice to get the Attorney General on the phone. She was now madly in love with Bobby, who had promised to marry her and leave Ethel, Lawford said, despite the Kennedy brothers ‘passing her around like a football’ and making her feel like a piece of meat. But when Bobby began to pull away, Marilyn threatened Bobby with a press conference where she would reveal her illicit affairs with Jack and Bobby and all the dangerous secrets she knew about the Kennedys and had written in the little red diary she kept hidden.Bobby demanded to know where the diary was. ‘We have to know’, he screamed at her, claim the authors. Marilyn was not going to give it up.Bobby’s first response was to call Dr. Ralph Greenson, Marilyn's psychiatrist, who she was also sleeping with and order him to go public with that affair.Lawford had learned about her affair with Greenson when he listened to tapes from the recording devices hidden in Marilyn’s house by the FBI, among others.‘Greenson had thus been set up by Bobby to ‘take care’ of Marilyn’…the authors write.The revelation would have ended Greenson’s career as well as send him to prison. But Marilyn had no intention of mentioning her affair with the doctor. Bobby just made him think that was the case.Bobby made his final visit to Monroe’s Brentwood house on the afternoon of August 4, 1962 with Lawford who went outside to have a glass of champagne poolside while Bobby talked with her.It turned into a ten-minute argument with Marilyn getting hysterical and threatening that, come Monday morning, she was going to call a press conference and reveal all – infuriating Bobby. He demanded no more calls, no more letters. Unwilling to accept being dismissed, she began screaming, grabbed a small knife and lunged at Bobby. Lawford, who had come back inside because of the tumult, grabbed her arm and knocked the knife away.‘Bobby thought we ought to call Dr. Greenson and tell him to come over,' Lawford said.Marilyn’s neighbors saw Bobby leave and re-enter later that evening with one of his two long-time personal bodyguards from the LAPD’s notorious Gangster Squad who performed illegal activities for the LAPD off the books.One of the bodyguards shot Marilyn in the armpit with intramuscular pentobarbital (Nembutal) to calm her down – after she was thrown to the floor by Bobby, who made this statement to the doctor in what the authors claim was a deposition confirming he and Lawford were at the house.While she was stunned, Bobby and Lawford rummaged through the house in search of the little red diary.The Nembutal injection wasn’t strong enough to calm her down for long ‘so the two LAPD Gangster Squad partners held her down, stripped her clothes off, and gave her an enema filled with broken-down pills containing anywhere from thirteen to nineteen Nembutals and seventeen chloral hydrates’. This did the trick. Back to the search for the red diary.Kennedy, Lawford, and the two bodyguards left the scene at 10.30pm and the incessant barking of Marilyn’s white maltese terrier, Maf, aroused suspicion of her housekeeper Eunice Murray and Murray’s son, Norman Jefferies who came over to find out what was going on. They discovered Monroe lying across the bed with her head hanging over the edge in the guest cottage and called an ambulance. Mrs. Murray suspected it was an overdose.Schaefer Ambulance attendant James Edwin Hall was first on the scene about midnight and threw Monroe onto the floor and proceeded to given her close-chest heart massage. Attendant Murray Liebowitz was also with Hall on the abulance run.‘She was naked. She had no sheet, no blanket. There was no water glass. No alcohol…We ascertained that her breathing was very shallow, her pulse was very weak and rapid and she was unconscious at that time,' Hall observed.Her bedside table had pill bottles all neatly capped. No water, no alcohol. ‘As I bend over her, it hit me – there was no vomit, unusual with an overdose which is what the woman managed to tell us that she thought was wrong. … there was no odor of drugs from her mouth. Another classic symptom’. This discredited any theory that she had ingested 64 pills in a suicide attempt.Hall started an external heart massage and got her breathing again. He worked an airway, a clean plastic tube, down her throat and Liebowitz ran to the ambulance for the resuscitation equipment.Liebowitz was about to retrieve the stretcher from the ambulance when a man appeared in the doorway. It was Greenson who firmly stated, ‘I’m her doctor. Give her positive pressure.’‘Jesus Christ, I thought. What’s wrong with you? I’ve got a machine here that’s doing a great job of that. Why take her off it’? Hall remembered.Hall removed the resuscitator and attached another short length of tube to the airway. The doctor pushed on Marilyn’s abdomen in the wrong place while Hall blew into the tube.‘I know some doctors aren’t used to emergencies but this guy was all thumbs. That’s when he muttered, "I’ve got to make a show of this". I never forgot that remark. "Christ, let’s move", I said. "You can work on her in the back of the ambulance".'Time was running out and I wanted to save her’.The doctor opened his bag and took out a hypodermic syringe with a needle looked about a foot long. 'He drew up a liquid from a bottle with a rubber seal and filled the syringe. He felt his way down her ribs like an amateur. Then he thrust the needle into her chest. But it didn’t go in right. It hung up on the bone, on one of her ribs’, said Hall.‘Instead of trying again, he just leaned into it, his cheeks quivered with the effort. He pushed hard and he drove it all the way through the rib, making a loud snap as the bone broke. I know he scarred that rib bone. I had watched a lot of medical procedures and this guy was downright brutal’.James Hall had worked for Schaefer Ambulance for some years. His father, Dr. George E. Hall was a Beverly Hills surgeon and former chief of staff of LA receiving hospitals, the city’s emergency system.His mother was a surgical nurse. His uncle, John Nance Garner, was Vice President for two terms under Franklin D. Roosevelt. He was a very credible witness to the nurder.Murray Liebowitz, the other ambulance attendant who witnessed the murder, never talked.(dailymail.co.uk)Bakudaily.az