dont you think you maybe could have had a word with them(and their parents)first, calling the plod on over anxious teens is a sure way to become a target. I was i kid myself once(honest!) and my curiousity often got the better of me , but a word in my shell like and i wouldnt do it again. The police are waste of time they are only there to catch you speeding. Phoning plod on youngsters is something victor meldrew would do. Fair enough if after you told them/parents they still did it.

just my opinion

cheers
jonathan