Agent Fields

Agent Fields was an FBI agent. He and his men inexplicably showed up to the shootout underway at the Peppermint Hippo, where Fields attempted to pull jurisdiction on Lieutenant Dawson. His relationship with Dawson mirrored that of Agent Tucker to Stan, Kyle[, Kenny and Cartman earlier.

Trivia

 * He could possibly be Agent Tucker's father.
 * Realistically, it should've been the DEA, and not the FBI, who showed up, as Gino was a drug dealer.