Personally I think he did. But OK. Let’s just say he knew about it and did nothing to stop it.
Knew about it but did not stop it. Possible, but not probable.
As a young man my grandfathers home was a congregation point for many Texas families. He was not a political man, but one of the men who visited was the son of a local doctor who delivered my father. He was the assistant attorney general of Texas for Many years. He loathed LBJ and I heard all the stories about things he had done. Stolen elections and a lot more. That was back in the days when all Texas pols were Democrats, before the Left took over the party.
He simply did not kill Kennedy. But yes, Lyndon did hate all the Kennedy’s.
My bet is on the Cuban Mafia. They had a score with John and Robert.