OK, last chance to bail. Massive spoilers ahead – you have been warned.

As you will be aware if you’ve seen the film, the murderer turns out to be Peter Crowley, a young man who lives with his domineering mother and, we discover, is a diagnosed schizophrenic. Now the fact that Crowley predates the film incarnation of Norman Bates by two years (and the novel by one) is certainly noteworthy, but despite making him the first person that Halloran pays an investigative call on, the film then goes out of its way to eliminate him from our enquiries and instead piles suspicion on both Dr. Fenner and the adulterous Mark Roper. The obvious reading is that Fenner and Roper are being set up as whale-sized red herrings in order that the film can then surprise us with the revelation that it was Crowley after all. Yet I would suggest that there’s another, altogether more interesting way to read this.

The key scene here is the one in which we are pushed to discount Crowley as a potential suspect and get seriously suspicious of Dr. Fenner instead. Fenner pays an unannounced call on Crowley, ostensibly to check his health but actually to forcefully accuse him of being the killer. If we take the revelation of Crowley's guilt at face value, then Fenner, who is aware of his psychiatric problems, genuinely believes that the boy is guilty and is attempting to break through his wall of confusion to get to the truth. But the aggressive tone of his interrogation is troublingly similar to that used by police and the military when trying to badger someone who did not commit a crime to confess to it anyway, the aim being to whip them into a whirl of confusion and distress so intense that they will admit to anything without realising what they’re saying. Given that Fenner is familiar with Crowley’s condition, this could well be his intent. That’s certainly how we’re initially encouraged to read it. But what if instead of being the red herring we later accept it as, this really is a case of a scheming doctor with a shady past deliberately implanting a false narrative into the head of susceptible patsy in order to cover up his own misdemeanour? This would mean, of course, that Halloran actually gets the wrong man (he only confessed, after all, in a moment of extreme terror), which only serves to confirm what I felt about the likely arrest record of this particular detective in the first place. And if you buy into that, the only question that remains is did Fenner do the murders, or was he in league with or covering up for Roper? I think we should be told.