What would happen if the FBI told Tony about Patsy being in his backyard with the gun and peeing in the pool?

The FBI could have easily told Tony that Patsy was in his backyard with the gun and might have been considering shooting Tony but pissed in the pool instead, they had it on video and could show it to Tony to humiliate Patsy and scare Tony into ratting, or show it the media and let the.tv air the footage.