Personally , I don ' t think LBJ did it , he was perhaps the most manipulative President we ' ve ever had , but not down right evil . However the day JFK was shot , Johnson swooped in on the opportunity . He called Robert , the attorney general at that time , to get his okay to do the inauguration . Robert thought Johnson was way out of line by instantly being inaugurated hours after his brother ' s death , he rather wanted Johnson be inaugurated after Jack ' s death . Johnson refused and later talked Robert into letting him take the oath . There ' s the great story that Johnson heroically waited for Jackie to board Airforce One before it could take off . The real reason why Johnson waited because inorder for the inauguration to be official , you need 15 witnesses , Jackie was the 15 th . A great picture explaining the inauguration LBJoathwithcaptions . jpgRobert received a call from head of the FBI , J . Edgar Hoover who simple said , Your brother is dead and hung up instantly . Robert would later say that he believed Hoover seemed pleased to tell him that . However I don ' t think of this as proof that the FBI did it , Hoover is just an insane man . After calling everyone over the White House to change Jack ' s locks and codes on everything , he scheduled a meeting with CIA director , John McCone and asked if the CIA had any involvement with Jack ' s death . McCone denied it . Robert later told investigator Walter Sheridan that he asked the director in a way that he couldn ' t lie to me , and they the CIA hadn ' tA good read I just read , simple but extremely well w r i t t e n B i o graphyPhilipLorddptelThis picture delves in onto the Mafia conspiracy quite a bit which I believe is to be the case into Kennedy ' s death . The Kennedy ' s relied on the Mafia heavily for election campaigns and wealth . Kennedy carried Chicago most likely with the help of the Mafia . It didn ' t help that Jack appointed Robert as Attorney General who would testify against several Mafia Kingpins , putting them in jail . Robert always thought that Jack or him would be assassinated by the Mafia , but he always thought it would be him , not Jack . Edit As pointed out by someone , Hoover was the head of the FBI , not CIA . My mistake !