Who is Jimmy Wells in After Twenty Years?

In O. Henry's short story "After Twenty Years," Jimmy Wells is a police officer who encounters his old friend Bob, whom he promised to meet twenty years earlier. As they converse, it becomes clear that Jimmy has changed significantly and is committed to upholding the law. Ultimately, he reveals his true identity and the reason for his actions when he discreetly informs the police to apprehend Bob, who has turned to a life of crime. This twist highlights themes of loyalty, friendship, and moral responsibility.