Is there any free web sites that will show if you have a warrant?

A unmarked car came to my mom's and said I have a warrant for my arrest and asked for my new address - wasn't given - I called the police station and they said they don't show one. They said it could be a civil warrant????? And to call back tomorrow. I want to know now. Does anyone know of a free site where you can check and see what it is for. Thanks