I was on this phone chatline and this man impersonated a police officer?

It happened this one night I happened to be on the chatline and I was looking for a friend to talk to maybe even hangout if we click.there was this one guy that messaged me saying he liked my greeting and that he would give me his number.so we talked on the phone and then he asked me do I mind him being a police officer and I said no.then he said that he is trying to catch son culprit that has been meeting women online and robbing them ani was really shocked so he asked can i help him catch him i said sure so he described the man and what he usually says to the women so i went back online but didn't have any luck so i told him and he started to get really mad saying that he is going to come to my house and arrest me.whay should i do? and i do feel he is a phony