I was in a Walmart parking lot (just pulling in on a street leading to it) and I get an X band. Thinking its just the door openers, but then realizing that they wouldnt go off from this far away from them. Then I see a black undercover cop. I pull in front of it (his car was parked), and X goes all the way up to X9, so i'm like whoa now, it really is a cop running X band. I stop in a parking spot, he pulls out, at first i'm thinking he's about to pull me over for something, but he just leaves. And I follow, lol! He turns down this road so I want to see how far I can get his radar, well lets just say not too far. But i'm pretty sure he just had his front radar on so I cant be mad about not getting good distance. But i turn around and actually go into walmart for what i indeeded on doing to begin with. When I come out and leave i see the same undercover cop again sitting in the parking lot with radar on. And by the way, he was running constant on. But just figured I let everyone know.