In many states it is not against the law to slow down, put on your hazard lights and proceed to a well lit, well occupied area. If in doubt you can call 911 and tell the 911 dispatcher what you're doing. They may tell you to stop, but if they do that, ask them to verify with which ever agency appears to be pulling you over, that it is in fact them pulling you over. Worst case scenario, the you stop and the creep walks up to your car, the 911 dispatcher is already on the phone with you and knows your location.
Indiana has 18 Mustang GT's working throughout the state . They are all different colors - blue , silver , maroon . There isn't even any type of antenna to give them away . Officers are required to be in uniform at all times when operating them .
But as the article states , a uniform is no guarantee it's a real cop . A few years back there was an impersonator with a state trooper uniform and blue light in his car that got his kicks stopping people at night and giving them verbal warnings around Livermore , KY . He never caused any real harm but finally stopped an off duty cop that ended his game .