>> even things like this, the eight ball. the rubik's cube. why do you have these out here on the countertop? >> everything in this office is pretty much wiped down after every deal in order to gather information from fingerprints if need be. >> police have rigged the shop with hidden cameras and we've been allowed to install some of our own. >> there's a sccamera hidden rit here. another hidden right here. h how dangerous is it for you to do an undercover operation? >> for the undercover detectives, it's very dangerous. you don't know who's going to pull out a gun. >> while the undercover officers are out front, they are under constant surveillance from this back room. >> so one of the deals is going down there are undercover officers right here, hands on their guns ready to pop out here in case something goes bad. >> the word is out on the street that the owners of the so called audio shop actually buy stolen