The Fourth Victim

• Carroll Baker was no giallo newcomer by 1971 — she'd already headlined a run of Italian thrillers starting with 'The Sweet Body of Deborah' (1968, dir. Romolo Guerrieri) and continuing through several collaborations with director Umberto Lenzi.
• The film's Italian release title is 'In fondo alla piscina' ('At the Bottom of the Pool'). It's also circulated under 'The Fourth Mrs. Anderson' and 'Death at the Deep End of the Swimming Pool.'
• Michael Craig, who plays smooth widower Arthur Anderson, had a decade earlier played heroic Captain Cyrus Harding in Ray Harryhausen's 'Mysterious Island' (1961) — a long way from a Eurothriller wife-killer.
• Inspector Dunphy, the cop who won't stop circling Arthur, is played by José Luis López Vázquez, a prolific Spanish character actor of the era.
• Carroll Baker's character talks her way into Arthur's life using forged papers and a fake name — while, in an odd production wrinkle, a second actress (Marina Malfatti) is separately credited as playing a 'Julie Spencer' too, a detail tangled up in the film's closing twist.

Arthur really did kill all three wives — car crash, fall, drowning — and each 'accident' worked because it was staged just plausibly enough. Marrying a fourth wife within weeks of his own acquittal isn't recklessness, it's confidence: he's testing how far the trick still works now that a jury has already decided not to believe a repeat accusation.

Inspector Dunphy isn't just a cop who can't close a case — his fixation on Arthur plays like something personal. The film never explains why he won't let it go, which is exactly the kind of loose thread that supports an obsessive-cop reading: he's chasing this case to make up for one he lost somewhere else.

'Julie Spencer' walking into Arthur's life under a false identity is more than a revenge plot wearing a wig. Two different actresses get credited as playing 'Julie Spencer' in this movie — which either means the film is hiding a double/impostor twist in plain sight from frame one, or it's quietly telling on its own tangled production history.

Arthur Anderson has buried three wives in as many years — one dead in a car wreck, one dead in a fall, one found floating in his own swimming pool — and everyone in town, including the jury that just acquitted him, is pretty sure he did it. Then a blonde named Julie Spencer turns up swimming in that same pool like nothing ever happened, and before long she's about to become Mrs. Anderson number four. Only "Julie Spencer" isn't who she says she is — she's working under forged papers and a dead heiress's name, convinced Arthur murdered someone she loved and determined to prove it from inside his own house. Inspector Dunphy keeps circling the case he can't close, everybody's got something to hide, and the film saves its nastiest, strangest twist for the last ten minutes.