I'm amazed at how many people here are OK with kids breaking the law and vandalizing another person's property. The kids will get a slap on the wrist, it won't be a big deal, but they will have to go through the system and they should have to do it. They'll get fined and possibly some community service. The penalty will be in line with the crime. If you let them go, what have they learned? they learned that they don't need to be accountable for their actions.
The law is there to be enforced. The kids should pay the price for their acts. Amazing how many people disagree when this issue is black & white.
BTW - I was a little bit of a hellraiser when I was a kid, and I'm glad I learned a lesson or two when I was a kid. Straightened me out.