Well, now that some JFK files have been released, it's a go…

https://www.abovetopsecret.com/forum/thread606838/pg1

Jackie was CIA, probably used to infiltrate the Kennedys from the start.

Might have been a Manchuria candidate, but even if she wasn't, at the time of the assassination she was estranged from her husband who was doing acid with his mistresses in the white house.

Watching the Zapruder film with the hypothesis in mind that she pressed a one shot derringer against his throat after the first shot didn't kill him, blowing his brains out upwards and away from her, is really hard to deny.

Especially because there is smoke in the air. Smoke is only where the gun is fired, not where the bullet hits.

This would also explain her strange behavior, especially climbing on the trunk. She might have "malfunctioned" and tried to give the derringer to the SS man behind, who told her to keep it.

If this is what happened, I don't expect to find anything in the documents about it.

If I had to bet, I'd say she wasn't supposed to do it, unless the snipers missed.

"When you come at the king you better not miss."

They had to make absolutely sure that he wouldn't survive the attempt.

When he was still alive after the first shot(s), she did what had to be done. Either consciously, or in a triggered state of mind control.