Motive?
Motives include:
—JFK fired Allen Dulles as head of CIA and vowed to destroy agency operations.
—JFK refused to allow Israel to get the atomic bomb while James Jesus Angleton was working with Mossad to get them the bomb.
—JFK had an affair with the wife of the London CIA Chief of Station—that guy was ticked off and wanted revenge.
There were other possible motives as well.