When a socialite is murdered, and the prime suspect is a cat burglar who broke into her house at the time she was killed. Later when the man is caught he claims that there was someone else who went into the house before he did. McCabe doesn't believe him and places him on trial and gets him convicted. But after the trial McCabe thinks something is wrong because the man is not known to be violent and later discovers something that proves he is innocent. So he thinks that someone else killed her, like the person the cat burglar saw enter the house or her husband.