Kitty is a good child to her parents and siblings, but she's a hell demon to her teachers. She's usually shamed for talking while working, cheating off other students, talking too loud, singing at inappropriate times and sometimes picking on kids who pick on her. Once, she even fought three boys! That was when she was in Kindergarten, hence 1 year ago (okay I make my characters age with current time lol)
When a character has major problems with authority figures, I recommend that you try to make sure that he doesnt come off as whiny and/or senselessly persecuted. Its ok if the cops dont treat him *fairly*, but make sure theres a REASON theyre mistreating him. For example, in Rambo, the cops hated Rambo because they thought he was a trouble-maker who didnt have a place in their town.