Without question the Palestinian radical and loon, Sirhan Sirhan.
The first killing shot came from Sirhan’s 22 cal (short) pistol directed less than a foot from RFK’s mastoid process (the little bump just below and behind the earlobe, both sides of the head, this one on his right side, from behind). There is no question about this round which was recovered from inside RFK’s cranium, and did not exit the cranium. A slow moving (relatively) round, the round of choice of professional hitmen and coached lunatics from the Palestinian movement as well.
US and Sicilian mafia improvements: take the round off the casing, remove some of the powder, to further slow the fps out the barrel and also reduce the sound of the pistol firing, requiring the killer to get in close, and so the round will rattle around the brain case destroying the brain. One shot one kill.
Sirhan did keep firing several times— there was only one round left in his pistol till it was removed from his hand.
The recent “questioning” of a 50 year old murder, has been brought up with wife cheater, beater and probable suicide causing.. RFK, Jr. (late CEO of the venezuelan oil company CITGO, with a 600k a year job managing the giveaway tax break given to CITGO by the State of MA for “free” fuel oil given to the “poor” of MA— from the non-profit front company RFK, Jr created and ran— for political expediency). RFK, Jr. is certifiably a loonatic, period.
Huey Long died after being shot by a doctor, who was shot dead by Long's bodyguards. I read that it's possible that the bullets which actually killed Long may have come from the bodyguards' guns--ricocheting off the walls in a confined space. Of course Sirhan wasn't shot dead on the spot.