CONTAINS SOME SPOILERS
I'll be the first to admit that outside of giallo and zombie movies, I'm not that knowledgeable about Italian cinema. To be honest, I'm not massively knowledgeable about the giallo and zombie movies except in contrast to "proper" Italian movies: Fellini, Rossellini, De Sica. And, indeed, Elio Petri. Which is hardly surprising, really: of the seventeen titles Petri is credited with as director on the IMDb, only three appear to have ever made it to regular release in the UK, and apart from the enjoyably strange (and very good looking) futuristic SF thriller The Tenth Victim, this considerably darker and moodier film is his only film to make it to British DVD and BluRay. A pity this has taken so long, because it's really rather good.
The essence of 1961's L'Assassino hinges on whether shady antiques dealer Alfredo (Marcello Mastroianni) is a literal or merely metaphorical ladykiller: has he murdered his older lover Adalgisa (Micheline Presle) so he can marry his extremely rich younger girlfriend? Of course he denies it, but given Alfredo's dubious character - he's not above handling stolen goods - the police aren't looking for anyone else in the case and would rather he confessed simply to save on the time and paperwork; even if he didn't actually do it, he's the kind of man who should be jailed for something.
Much of the film is centred on the battle of wills between Alfredo and the veteran cop on the case, Palumbo (Salvo Randone): he ignores Alfredo's constant denials in the hope of wearing him down to the point where he'll give up and confess to everything. In truth, though, it doesn't really matter who the killer is: L'Assassino is more a character study of an outwardly respectable but very shabby individual than a whodunnit and the murderer's real identity is almost an afterthought.
With a music score consisting principally of one jazz record, and wonderfully shot in grim black and white, it's blessed with occasional touches of humour (such as Alfredo's two irritating cellmates undoubtedly put there by the police to further pressure him into a confession) and human sadness. The most tragic moment occurs when Alfredo's mother comes to Rome to visit him, and you can see the disappointment in her eyes: he doesn't even hang around to watch her bus leave for home. As mentioned above, this isn't an area of film I have much familiarity with, but I liked L'Assassino a lot and well worth catching.