In the scenario, a murder had been committed, and it was the duty of the police and detectives to determine and apprehend the culprit. If we assume that the paranoid man was in fact innocent, then it follows that by jumping in and trying to make it be all about himself, he was interfering with the investigation and - intentionally or not - thereby increasing the chance that the real murderer would escape justice.
What does he really want? For murder not to be considered a crime, just so that people won't accuse him of it?