So this is a weird movie in two ways.

The first way is that it’s unusually serious as a murder mystery — it’s probably the giallo that’s the most focused on detective work and trying to solve the crime, rather than the killer’s activities. The killer does kill, sure, but they’re doing so one step ahead of the detective, trying to thwart the investigation. Even the cop himself notes that if they hadn’t bothered to investigate the first murder, these other people would still be alive.

The second way is that it has a really obtrusive pedophilia subplot. The first murder is of a little girl and her father, who were kidnapped for ransom. In the course of the investigation, the detective talks to all the family members. Each of them has their own dark secret and motivations, and the movie really amps up the drama here. But then there’s the uncle who used to “spend a lot of time with” the girl, the servants say with significant glances.

I wasn’t sure if I was reading too much into this, but then when the detective goes to that guy’s house, at one point an actual naked little girl comes out, and the dude is all “uh, she’s a model for my paintings.” So first of all, a) what the fuck, how is it legal to put a naked kid in a movie?!? Even if it was legal in the ’70s in Italy, I’m genuinely shocked that it’d be legal to sell this movie in the US in the present. Extremely disconcerting. But also b) the cop doesn’t seem to believe this guy’s story (because it’s not believable), but also does literally nothing about this. Really really feels like there probably should have been an immediate arrest/investigation of that guy wholly separate from the murdering.

Wikipedia says of this:

[Director] Tonino Valerii said the pedophile uncle’s character was completely rewritten in the process. “It was a character that you could not tell what he was in the film for, so we told ourselves, ‘Either we take it out of the film or we develop it’. And we had the idea of the naked little girl that appears at the door of his studio during the commissioner’s visit…”

PROBABLY SHOULD HAVE JUST TAKEN IT OUT.

So yeah, on the one hand, this is an above-average murder mystery with great characters and lots of twists and turns. But then there’s this one giant element that — even though it’s very brief in the movie, and not incredibly significant to the story — just looms over it with a giant wtf.