Manny Martinez, codenamed 'Sinatra', is a part-time agent of JFIC.
That acronym stands for the Joint Federal Investigations Commission. The organization is "unreported within the opaque hierarchy of the FBI". "Their mission - arrest the untouchable and do it without attracting attention". That mission sounds impressive, albeit purposely vague. Put another way, "we apprehend high-priority fugtives. Domestic". That clarifies things a tad but it also indicates the work is criminal apprehension and not spy-related except some of the people that JFIC and Martinez will be going after pulls it back into the fold.
A bit more informative is "JFIC is a top secret Special Access Program, hidden within the FBI's intelligence hierarchy. We are unacknowledged and unreported by the FBI, or any other agency. Very few know of its existence for deniability concerns." Add to that, "It begins when our oversight board becomes aware of a target or situation threatening volatility. Our government hates messes. Most messes, they want gone and don't want to know how or why. So I am contacted. I use the considerable resources extended to me by all five agencies aforementioned to do my research and make a decision; is this a job for my department or not? I handle fugitives who are high-profile, high-risk, politically connected, or extremely dangerous-not the kind advertised on the FBI's most wanted list. There is a secondary list, a worse brand of monster. These are fugitives the public is better off remaining ignorant of, and sometimes these targets are best handled without the use of overwhelming force."
The "I" in the above paragraph is FBI Senior Special Agent Weaver, the former Marine officer who runs the day-to-day operations of JFIC. "It is a small organization," she tells Martinez when they first meet. "How small? I am the only full-time staffer. No Christmas parties, no commemorative badges, no office potluck - we're lean and mean." When the oversight board nominates a target, that name is passed to Weaver. "If I decide the target fits JFIC's criteria, I select one or more of our agents and we get to work. The operation is buried deeply within the veils of secrecy politicians provide to keep their hands clean. Don't ask, don't answer." At that point, "I coordinate independent agents nationwide. Think of them as sleeper cells, ready to be activated for temporary assignment".
Which explains a bit the "part-time agent" moniker mentioned above.
First and foremost, Martinez is a U.S. Marshall and has been for two years. Prior to that his life is a bit vague and he has had to deal with PTSD from time to time as a result of it. He took to the action in the Marshall's Service quickly and loved it though after a couple of years he has found a few too many periods of sitting a desk being bored or worse yet doing paperwork. That's why the chance to pulled away from time to time to handle especially tricky and dangerous missions so attractive.
Martinez loves action. He loves flashing cars (he drives a slicked-up Camaro when we first meet him) and routinely clothes himself in Brooks Brothers suits. He is glib and educated though he loves to fall back on a "lowly Puerto Rican" background to make himself seem less so. Most importantly to him, is, as mentioned, the action!
Oh, the codename he uses - Sinatra. He picked it when he was first approached to be part of JFIC. He insisted on it, as a matter of fact. It was a deal breaker. "he's one of the great Americans of the twentieth century. Hardworking, stylish, and tough. I love his music, plus white people relax around a guy named Sinatra rather than Martinez."
- When Martinez's partner in the Marshalls comments in jest that Martinez is "an ass", Martinez responds, "Word you're searching for is hero."