If you won't tell him what he wants to hear, Jack will torture you in horrible ways, and—oh, wait, no. That's Jack Bauer, the Keifer Sutherland character from 24.
This guy is Jack Baer, the FBI Special Agent who interviews Arkosh Kovash, the burned Hungarian survivor of the boat massacre.
Baer functions as an important information tool. He finds out about Keyser Söze from Kovash and then relays this info to Kujan, along with the fact that the Argentinean boat gangsters weren't dealing drugs—they were trading a snitch, Arturo Marquez, to Hungarian gangsters who were rivals of Söze.
So that's all you really need to know about Jack Baer.