Bill Collins' superior in the A.T.F. Chicago office, George Black is, in fact, part of a gun-running operation which he co-ran with Edward Haints, an Illinois assemblyman running for mayor in Chicago under a gun-control platform. It was Black who had contracted Radinov to kill Jonathan Washington, the only witness to the operation, for which he provided her with a cardkey with Collins' ID, as well as Rally and May for helping Collins. He also supplied Radinov with the use of a supposedly shut-down A.T.F. safehouse for her to stay in.
But after the first attempt to kill Rally went awry, Black filed a vacation leave and decided to flee the country. He proceeded to the suppositly-shut down safehouse where he knew Radinov was. When he got there, he discovered that his partner Haints was talking to Radinov on the phone, with Radinov aiming her Weldrod suppressed pistol at him. Realizing he'd been double-crossed, he tried to persuade Radinov to tell Haints not to kill him, but to no avail. Radinov shoots him, once in the chest and once in the head. Black's body, along with the safehouse Radinov was staying in, was destroyed by a booby trap set by the assassin, which killed A.T.F. agent Jodi - but not Collins, who barely survived.