Santos Traficante supposedly confessed that he and Carlos were involved in the hit right before he died according to Frank Ragano. Ragano recounted what Santos said in Sicilian that Carlos messed up and should have hit Bobby instead.
Proof? No. Of course not. There will never be an end to this mess. But the account makes sense.
https://www.maryferrell.org/pages/Santos_Trafficante_-_It_Should_Have_Been_Bobby.html
Execution details? Who knows? Oswald was one of the shooters and patsy based on hard evidence. Likely a 2nd shooter behind the fence where the puff of smoke was seen for the fatal head shot.
While there are countless people and organizations with motives — the hate for Bobby was up close and personal with Carlos who was grabbed and put on a plane to Central America and left in the jungle to die. He barely made it out with his life.
When the mob picked up Carlos he said he would kill Bobby. However he took out JFK instead. “Marcello told Ed Becker that “the dog {President Kennedy} will keep biting you if you only cut off its tail {the attorney general},” but the biting would end if the dog’s head was cut off.”
https://www.thegirlwhoshotjfk.com/main-figures/carlos-marcello-1960-1963/
The Zapruder film ends with a view behind the fence. Nothing there.