The driver used his left arm underneath his right shoulder …

The driver used his left arm underneath his right shoulder I've seen the footage a whole bunch of times and they used the CIA heart attack gun (which agents freely showcased in front of Congress for separate reasons) with a poison projectile like they wanted to make sure he was dead three times over no mistakes.
That is not nonsense. The follow up "debunkings" have all of familiar tells of misdirection when confronted with subversive evidence.