Agent Schreck (first name unknown) is an FBI agent responsible for leading a sting to catch internet predators. He ended up sending his own men into a sting led by the NYPD, which greatly reduced the number of the arrest since many attendees in an in-person meeting were undercover agents.
Schreck and Captain Cragen fought with each other over the twist in their colliding operations, Cragen himself pointing out because they don’t work together, the predators are all still at large. (SVU: "Chat Room")