Would this be an appropriate situation to resort to calling the cops?

Okay, well this 18 year old boy on facebook added me and like five other of my friends who are my age (15).
We started texting and he seemed pretty friendly at first, but then he kept asking if I could come down to his house and f***!
My other friend just now told me he kept texting her and telling her the same thing!
We are pretty ticked off right now! I have already blocked him from facebook and I am wondering how to block his number from his phone (or I will simply just ignore all his texts/calls).
Do you think it would be appropriate to report his ass to the cops?
He is harassing young girls and attempting to engage in sexual intercourse! Do you think I should just ignore this guy and I am just over reacting? What should I do?