file sharing and the law

What i want to know is that , I am actually a user that bought the limewire program , and since i did that is my name being handed over to the authorities for investigation into whatever i might be downloading what ever it may be legal or not ...... I want to know how these people are getting the names of users ... or for that matter there ip addresses, It has to come from somewhere. By the time they get to your provider they have had to learn the information from one of these file sharing companies. Is Limewire selling me out ? (that of course is if i am actually doing anything wrong)