Katt Williams is under criminal investigation for committing a deadly form of whip lash ... so claims a man who says the comedian used his Rolls-Royce in an attempt to mow him down.
Katt was tooling around near LAX Tuesday ... when a guy named Glen Jackson pulled alongside and tried to snap a cell phone pic. Jackson says it triggered a volcanic reaction from Katt.
Katt and a bodyguard allegedly got out of the car, tried grabbing Jackson's phone, then pepper sprayed him.
Jackson says he stumbled out of the car, choking from the fumes, when Katt rolled his Rolls smack into his leg ... then doused him in pepper spray again before driving off.
Inglewood police are investigating a possible assault with a deadly weapon -- the Rolls. They'd like a chit chat with Katt and the bodyguard.
It's the 4th violent confrontation with Katt in 2 weeks ... two altercations on PCH ... and an alleged gun attack at an L.A. comedy club.
We reached out to Katt ... so far no word back.