it seems like a pair of impossibly accurate shots.
Kennedy was only 81m away when the fatal shot hit him, the best snipers can hit targets over 10x further than that, take Army sniper Adelbert F. Waldron:
“One afternoon he was riding along the Mekong River on a Tango boat when an enemy sniper on shore pecked away at the boat. While everyone else on board strained to find the antagonist, who was firing from the shoreline over 900 meters away, Sergeant Waldron took up his sniper rifle and picked off the Vietcong out of the top of a coconut tree with one shot (this from a moving platform). Such was the capability of our best sniper.”
That's 900m away from a moving boat...