Unfortunately he wasn’t a felon and had a permit, which is why he hasn’t been arrested.
He was, however, attempting to shoot Mr. Rittenhouse when Mr. Rittenhouse shot him.
That's what he claims. Has it been proven?
I seem to remember that he did have a felony on his record. ... or at least that was his record reported shortly after the time of the shooting. Nevertheless, the movies indicate that Mr. Rittenhouse acted in self defense. Mr. “Lefty” had aimed the illegal pistol at Mr. Rittenhouse just before he was shot. He actually tried to trick Mr. Rittenhouse into lowering his rifle before he was going to shoot him.