Do it. If you don't for sure nothing will be done. If you do, there is a small chance that something will be done. Years ago we got threatened by a nutcase in a car with the usual profanities. We reported him to the police. Evidently, so did others. He was charged with assault and we saw him in court months later. He was convicted with a probation. Although he didn't do jail time, his legal fees alone probably made him think twice about doing this the next time.