u already filed a police report the first time if i recall correctly

contact at least 1 other person that has also had theirs keyed or at least another witness who can say that it's been a pattern

u can even catch him in the act WITHOUT it being your car getting keyed

or u could also leave him a note on his car telling him you have footage of him keying people's cars and threaten to go to the police if he doesn't make things right

the camera is the best route to go bc it sounds like he's not stopping anytime soon