If you want an actually serious answer as to the who, how and why of the assassination and have three hours to spare, I would recommend Sean Munnger (A leftist university professor of modern political history) far to exhaustive series on the topic. For just the CIA, that starts at the 30min mark of Part 2, but builds a bit on previous debunkings.
This is a funny accusation in light of the amarican situation where our leader openly owns multiple businesses in Russia and other foreign nations, to say nothing of selling pardons or any of the other blatant corruption.