My father was the chief law enforcement officer in this country," Robert F. Kennedy Jr. recently told The Washington Post. "I think it would have disturbed him if somebody was put in jail for a crime they didn't commit." Kennedy's second oldest son now believes ... that his father was killed by a second gunman. RFK Jr. even visited Sirhan Sirhan, the man convicted of shooting and killing his father, because he was "curious and disturbed by what I had seen in the evidence." He isn't the only one. "If you believe the LAPD reports about this case, there is no way that Sirhan did it and did it alone," Dan Moldea, an investigative journalist and author of The Killing of Robert F. Kennedy, told Boston.com. Kennedy was assassinated ... on June 5, 1968, at the Ambassador Hotel in Los Angeles. Kennedy was walking through the hotel kitchen pantry [and] was shot from behind at point-blank range. Sirhan approached from the front, on Kennedy's right. His gun never got closer than about a foot-and-a-half away [and] carried a maximum of just eight bullets. And yet, there's evidence that suggests more than eight shots were fired. Who would the second gunman have been? Theorists most commonly point to ... Thane Eugene Cesar. Cesar was a security guard who hated the Kennedys. Cesar was also walking with Kennedy when the shooting occurred and ... owned a .22-caliber similar to Sirhan's gun, which he initially told police he sold before the assassination, but had actually, it was later found, sold three months after the shooting.