Sirhan Sirhan could not have fired all the shots and was not even in position to fire the shot that hit RFK in the head.
"The location of Kennedy's wounds suggested that his assailant had stood behind him,
but witnesses said that Sirhan stood facing west, about a yard away from Kennedy,
as he moved through the pantry facing east. This has led to the suggestion that a
second gunman actually fired the fatal shot, a possibility supported by Chief Medical
Examiner-Coroner for the County of Los Angeles Thomas Noguchi, who stated that
the fatal shot was behind Kennedy's right ear and had been fired at a distance of
approximately one inch. Other witnesses said that as Sirhan approached, Kennedy
was turning to his left, shaking hands, facing north and so exposing his right side."
-- Wikipedia
The best book is "The Killing of Robert F. Kennedy: An Investigation of Motive, Means, and Opportunity" by Dan E. Moldea.
"In November 2006, BBC Television's Newsnight aired a 12-minute screening of Shane
O'Sullivan's documentary
RFK Must Die. O'Sullivan stated that while researching a
screenplay based on the Manchurian candidate theory, he "uncovered new video and photo-
graphic evidence suggesting that three senior CIA operatives were behind the killing of the
Senator". He claimed that three men seen in video and photographs at the Ambassador
Hotel immediately before and after the assassination were positively identified as
CIA operatives David Sánchez Morales, Gordon Campbell and George Joannides.
Several people who had known Morales, including family members, were adamant that
he was not the man whom O'Sullivan claimed was Morales. After O'Sullivan published
his book, assassination researchers Jefferson Morley and David Talbot discovered that
Campbell had died of a heart attack in 1962, six years before the assassination. In
response, O'Sullivan stated that the man on the video may have used Campbell's name
as an alias. He then took his identifications to the Los Angeles Police Department, whose
files showed the men he identified as Campbell and Joannides to be Michael Roman and
Frank Owens, two Bulova sales managers attending the company's convention at the
Ambassador. O'Sullivan stood by his allegations, stating that the Bulova watch company
was a "well-known CIA cover".
Looks like the RFK case attracts die-hard kooks as well.