...Like the murder of his brother John almost five years earlier, Bobby's shooting was a watershed for America. Most people believe a lone assassin - a Palestinian refugee Sirhan Bashara Sirhan - was responsible for his death.
I shared that assumption until my continued involvement in political debate brought the real questions about Bobby's killing to my attention.
After studying documents, talking to experts and interviewing a crucial witness, I believe there is strong evidence that Bobby's killing was carried out by more than one gunman. And, more shockingly, that the Greek shipping magnate Aristotle Onassis paid for the assassination.
Stand by for Vaughn to channel those tin foil hat rays to explain to us why Sirhan Sirhan was not the real assassin despite that gun inconveniently in his hand pointing at Kennedy at the time of the shooting:
So was Bobby Kennedy's shooting a non-controversial, open-and-shut case with a single, obvious suspect? Here's a summary of the facts.
Firstly, Sirhan was apparently not in the right place to fire the bullets that killed Kennedy. The autopsy shows Kennedy was shot from behind, from below, from the right and with a gun positioned no more than three inches from his head.
Yet all the eyewitnesses said they saw Sirhan between one-and-a-half and five feet in front of Kennedy - a completely different location to the one he would have needed to be in to fire the fatal shots. This information was withheld until after Sirhan's lawyers conceded his guilt.
Using the US Freedom of Information Act, Bernard Fensterwald, a Washington lawyer, obtained an FBI report on the shooting in 1976. It indicated that at least 12 bullets were fired in the hotel kitchen that evening.
Two were recovered from Bobby's body and five from the bodies of wounded bystanders. Two more passed through Kennedy's body, while three were found lodged in ceiling panels.
And five more bullets were found embedded in the grassy knoll. Now back to Vaughn:
Sirhan appeared badly disorientated after his arrest, and when he was given a psychiatric examination before his trial, he was found to be susceptible to hypnotic suggestion, even climbing the bars of his cell like a monkey upon command.
In all probability, Dr Spiegel suggests, Sirhan was still in a state of hypnotically induced amnesia.
When I count to three, The Man From U.N.C.L.E. will wake up and actually think he is rational.
These questions continue to attract interest from a few intrepid researchers. Was there a second or even a third gunman? If so, who was it? Could the security guard behind Kennedy who admitted pulling his gun have had something to do with the killing? And, assuming that more than one gunman was involved, who was the mastermind behind the plot?
Even those most eager to blame the crime on Sirhan do not pretend he had the intellect, resources or the organisational ability to pull together an assassination conspiracy.
I've got it! The real culprit was Ilya Kuryakin. Hey, it makes just as much sense as Napoleon Solo's wild speculations:
Despite - or perhaps because of - his resentment of Bobby, Onassis gradually became socially and romantically entangled with the Kennedy family.
He met then-Senator John F. Kennedy and his wife Jackie in 1956 when he invited them aboard his yacht, the Christina. Shortly after JFK became President, Onassis began an affair with Lee Bouvier Radziwill, Jackie's sister.
But Onassis wasn't satisfied with Lee - he wanted Jackie herself. He took advantage of the First Lady's vulnerability in August 1963, shortly after the devastating death of her two-day-old son, Patrick. Jackie accepted his invitation to stay on the Christina while she recuperated.
For Bobby, the way Onassis thrust himself into the Kennedys' personal drama heightened the hostility between them. Onassis, of course, went on to marry Jackie in October 1968, five years after JFK's death.
According to Evans, the notion of killing a Kennedy did not take shape in Onassis's mind until early 1968 when he met Mahmoud Hamshari, a follower of Yasser Arafat and a fanatical anti-American and anti-Israeli activist.
Is this not starting to sound like a rejected Man From U.N.C.L.E. script? Vaughn then provides us with the romantic angle:
Then there is Hélène Gaillet, one of the players in Evans's story, whom I have interviewed myself. On an autumn afternoon in 2007, I met Helene at her apartment on New York's Upper West Side.
Statuesque and elegant, Hélène had worked as a photographer for The New York Times and New York magazine.
Hélène met Onassis for the first time at the Coach House restaurant in New York in the early Seventies. As the dinner came to a close, he raised the palms of her hands to his lips and said: 'The next time you are in Paris and need a place to stay, call me.'
In 1973, she was due to cover the fight between George Foreman and Muhammad Ali in Zaire. But when it was postponed for a month, she found herself in Paris with time on her hands.
Hélène remembered Onassis's invitation and called him. Fifteen minutes later, he invited her to his estate on the Greek island of Skorpios.
Onassis's daughter Christina was there. She was worried about her father's welfare and made Hélène promise not to take any pictures of him. Onassis was dealing with some difficult business issues, Christina said, and she was worried that any unflattering pictures would make him more vulnerable to his enemies.
During her visit to Skorpios, Hélène stayed on Onassis's yacht while he remained at his estate. One day, they went skinny-dipping and he came on to her. Helene reciprocated enthusiastically. It was the first and last time that happened between them.
Stop right there. The fact that Vaughn thinks some woman was turned on by that little toad, Onassis, puts this entire story into doubt:
A few days later, Hélène dined with Onassis at his beach house. They talked about many things, including religion. Hélène had been raised a Catholic and Ari questioned her closely, saying he was fascinated by confession and absolution.
In the course of the conversation, she asked Ari whether he agreed with Hemingway's famous remark about the difference between rich people and the rest of us - 'They have more money'.
With a laugh, Onassis replied: 'The rich get laid more, I know that ... Even that little runt Bobby Kennedy got laid more.'
More disturbingly, Onassis went on to speak freely about Bobby. According to Hélène, Onassis's hatred for him was still vivid and intense.
In the small hours, Onassis walked Helene to the beach from where a launch would take her back to the Christina. They stood together, gazing out to sea, for a long time.
After a while, Hélène realised Onassis was talking to himself, in low, murmuring tones, like someone deep in prayer.
Finally, as she strained to hear what he was saying, he turned to her and, clearly and simply, said: 'You know, Hélène, I put up the money for Bobby Kennedy's murder.'
Paging Oliver Stone! Hopefully if such a film ever comes to the big screen, barf bags will be passed out to the audience for when they retch during the scene where Hélène supposedly throws herself at the scaly Greek tycoon. Oh, and did Robert Vaughn say whether his book is fiction?
