The minute Officer Bellingham sets foot on the pages on Chains, we know he means business. Can we expect anything less of "An official looking man in a somber black coat" (5.24) whose duty is to arrest anyone seeking to subvert the rebels' control of New York? We think not.
One thing's for sure: There's no fooling this guy, and if he suspects you of something, he doesn't mess around. When Lockton lies to him and says that he is a supporter of the Patriots, for example, Bellingham is quick to call him on his dishonesty, telling him, "I don't have time for your games" (5.46), and threatening him with arrest once he finds something.
Bellingham's take-no-prisoners attitude toward the British isn't the only thing that makes him so interesting. He also seems to place quite a bit of trust in Curzon, a strange attitude for someone who owns slaves. Curzon seems to rise above his role as a slave and becomes an associate to Bellingham—he accompanies Bellingham to the docks to investigate the Locktons on their arrival and serves as a spy for the Patriot cause.
What makes Bellingham's view of slaves somewhat complicated, though, is how he treats Isabel when he comes to investigate her report of the money in Madam Lockton's underwear drawer. He doesn't find what he's looking for because Lockton moved the money, but Bellingham chooses to arrest Lockton anyway. On his way out the door, however, Isabel recounts that he "cut his eyes at me. They drilled a hole right into my fear of discovery" (11.62). While we can't say for sure, he seems to be accusing her of deliberately causing trouble by lying.
Still, at the very least, Bellingham is the catalyst that puts Isabel's desire to win her freedom by spying into motion.