Unusual crime picture even for the period. Most of these British pictures focused on the crime or an innocent caught up in nefarious activity, not just a straightforward police procedural before the term was even invented. In fact, the plodder was more likely to be a private eye or gifted amateur like Hercule Poirot or Miss Marple.
The title doesn’t refer to mystery but the painstaking element of putting all the pieces together and most likely still not being able to complete the puzzle – as occurs here until the very last scene and even then by pure accident. There are no sudden sparks of insight and the detectives don’t have the luxury of gathering all the suspects in a room Agatha Christie style. In fact for most of the movie not only can they not settle on a suspect they’re struggling to identify the victim. And this being when forensics didn’t exist except for fingerprints, there’s nothing even from that area to help.

At first Detective Inspector Fred Fellowes (Jack Warner) and Det Sgt Jim Wilks (Ronald Lewis) are investigating a break-in at a real estate office. Nothing’s been taken except leases, which suggests someone who either wants to get out of a lease or who doesn’t want their handwriting identified. After an exceptionally long haul it proves to be the latter. A lead takes them to a house in Brighton where they find the corpse of a woman with the initials JS.

I doubt if any police pictures of the period went into as much detail in following clues as this. Hunting for the killer the police interview taxi drivers, delivery men, garage mechanics, grocery clerks, truck drivers working construction, hardware and vacuum cleaner salesmen. Searching for the victim they check out beauty parlors, factories, pawnbrokers, airlines and hairdressers. The only clues are a gray car with a bent wing mirror – but even when they can identify the make it turns out there are thousands in the country – the contents of a vacuum, perfume smells on a pillow, particles of bone found in a furnace. Finally, with an old-fashioned trick Fellowes finds a name – Jean Sherman (Yolande Donlan) – and an address.
But Jean Sherman isn’t dead, though it transpires that she had a one-night stand in the murder house with a man she identifies as Campbell. But they can’t find Campbell either. They do alight on dodgy vacuum cleaner salesman Clyde Burchard (Michael Goodliffe), who has a previous conviction for indecency. Despite being identified by the delivery driver, it turns out he just had sex with the dead woman and nothing else.
Eventually, Fellowes finds Ray Tenby (John Barron) who is identified by Jean. He had picked her up after killing the other woman, Joan (Moira Redmond), and had sex with her in the next room to the corpse. But they can’t prove Tenby didn’t act in self-defense, and it’s only by that piece of unexpected luck that they can pin it on him.
Although most of the dialog focuses on the investigation there are some clever remarks. A journalist pressing a beat cop for information is told that leaving his car running unattended is an offence. Jean’s hardline father (John Le Mesurier) initially decries his daughter’s behaviour as immoral to the point of almost disowning her until, discovering she is dead, he bursts into tears.
With the amount of mileage the investigation covers, this could be done within the usual hour-and-a-bit of the standard British B-movie so it stretches a proper feature length. As written and directed by Val Guest (Assignment K, 1968), it’s not particularly stylistic, nor does it stretch tension too far, but it is still engrossing in the accumulation of detail.



