How do I get back at someone who trashed my car?

Ok, well it's not really my car it was my girlfriends truck but two of her ex boyfriends went to her house while she was asleep and smashed it up. The repairs cost over 600 dollars not to mention the profanity they painted all over it. I know both of the guys who did it. They're not nearly as bad *** as they sound, one's a creepy stalker who she dumped a year ago and he still follows her places and one just thinks things like this are a joke and he finds them funny, And we told the police but they werent able to do anything about it. So what could I do personally to get back at the guys? any suggestions?