How to find out if someone is a State Trooper?

I just wanted to know if anyone could tell me how to find out if someone is a NC State Trooper.I am talking to this guy and he said he was a Trooper.But before I meet him in a public place I want to know for sure.He ask me to a Troopers banquet and said I would know when he picked me up in his patrol car to go.But I want to find out before I go and I don't want him to know I am checking.