How does the law play into the story?
Though the issue of criminality is central to the entire story, it is only at the end of the novel that Holmes relies on actual legal action. This reticence to involve the law indicates several things. First, law requires firm evidence, not simply Holmes's brilliant deductions. Thus, Holmes has to wait until he can find firm proof of theories he has already proven to himself. Secondly, the delay suggests a certain ineptness on the law's part. The law cannot really catch a criminal until he has already committed his crime. The law's seeming inability or unwillingness to use methods like Holmes's means that it is always behind the ball. In this case, Holmes has to put Sir Henry in danger in order to prove his theory, suggesting that the official law faces a stumbling block towards protecting citizens.