Guerrero works with Christopher Chance and Winston. He's considered the company's muscle and/or hired gun, often getting directly involved in Chance's adventures.
Winston: Martin's father said the feds told him, the only way they can go there if it was a matter of national security.
Winston: Well, we're going to make it one.
Winston: All right, what the hell's going on? You heard me.
Guerrero: There's a guy out there, been looking for Chance for awhile. Just got one step closer I guess.
Guerrero: His old boss.