One Piece Chapter 3, page 8: Chapter 3: Enter Zolo: Pirate Hunter

Koby panics, screaming, "If you let him loose, he'll kill us then wreck the town!! That's suicide!!" Suddenly, Zolo looks up, notices them, and calls them over, asking them to untie him. He smiles menacingly, claiming he has been tied up for nine days and offers to capture a high-bounty target and give them all the money in exchange for his freedom, assuring them, "You can trust me. I'm a man of my word."