Kennedy was gunned down on June 5, 1968, at the Ambassador Hotel in Los Angeles, a few moments after claiming victory in the California presidential primary. Sirhan Sirhan, the Palestinian immigrant convicted of killing him, remains in a California prison.

David Talbot, author of "Brothers," a book about Kennedy's investigation of President John F. Kennedy's assassination, listed some mysteries for the San Francisco Chronicle. Those include discrepancies in the number of rounds Sirhan could have fired and the number of shots on a radio reporter's tape and a coroner's finding that the fatal shot was fired at almost point-blank range, although Sirhan was several feet away.

Sirhan himself told an interviewer some years later that he could not remember the shooting -- he said he was in a hypnotic trance -- and also could not remember writing "RFK must die" in his diary.