Underrated early Dario Argento giallo which features his usual stylish touches. It's a thriller that subscribes to the theory that a murderer's homicidal nature can be discovered by studying their chromosomes.

Someone breaks into a genetics laboratory, and shortly after one of the lab's technicians is murdered after someone pushes him in front of an oncoming train.

Newspaper reporter Giordani (Franciscus) teams up with blind man Franco (Malden) to discover if there's any connection between the two seemingly exclusive events. But as more bodies begin to pile up, it's more a matter of 'why' than of 'if'!

Handsome film helped by a beaufitul score from the amazing Ennio Morricone...a work as haunting as anything he did for the famous spaghetti westerns.

Malden and Franciscus are both captivating performers, memorable 'hands on' climax.

Followed by the last chapter in Argento's animal trilogy, Four Flies on Grey Velvet (1971).