Kennedy has joined calls for a re-investigation lead by Paul Schrade, the former western regional director of the United Auto Workers, who was also shot in the head at the Ambassador Hotel in Los Angeles.

Robert Kennedy, Jr. has concluded there may have been a second gunman and is now publicly urging a re-investigation into the assassination his father, Sen. Robert Kennedy (D-NY), The Washington Post reported Saturday.

After months of research, Kennedy met in December with Sirhan B. Sirhan, the man convicted of killing his father. The December meeting at the Richard J. Donovan Correctional Center reportedly lasted for three hours.

“There were too many bullets,” Robert Kennedy Jr. told The Post. “You can’t fire 13 shots out of an eight-shot gun.”

Kennedy, an attorney like his father, dismissed Sirhan’s trial as “really a penalty hearing.”

“It wasn’t a real trial. At a full trial, they would have litigated his guilt or innocence,” he explained.