If there are rumors about him having a criminal record, try to do a free criminal background check on him. Nothing may come up because he is a minor, though. Watch his action closely, when he is in situations that mirror what the rumors are about.
Rumors are not always truths. But it is better to be safe then sorry. Sometimes, if someone gives you a bad vibe, it is better to just get away from them instead of waiting for proof that they are bad news.
