Two years before Zodiac, Capote depicted Truman Capote making a fuss about possibly not having an ending for his seminal true crime novel In Cold Blood. Robert Graysmith, on whose non-fiction books Zodiac is based, had no such qualms, nor did director David Fincher. The comparison may be unfair; Graysmith is no Capote (but then, who is?), and In Cold Blood isn’t a whodunit – though technically neither is Zodiac, since after more than two hours we don’t learn who [has] done it so much as who-a-very-small-group-of-people-think-done-it. In a nutshell, this is a movie about a hunch.

The film would work better (and that’s not to say it doesn’t work at all) if it were, like Capote, about a man obsessed with a crime and those who have committed it – especially considering that the Zodiac killings constitute arguably the most famous unsolved murder case in American history; unfortunately, Fincher is what James Randi would have called a true believer, and Zodiac leaves little doubt that the director is as persuaded that Arthur Leigh Allen (John Carroll Lynch) was the Zodiac as he is that Herman Mankiewicz singlehandedly wrote the script for Citizen Kane.

Zodiac is a better movie than Mank, however, because Fincher was more in possession of his faculties in 2007 than in 2020; accordingly, the former film makes a more coherent and convincing case for its thesis than does the latter (and even this we can attribute to the credibility of a very deep roster of skilled supporting players in addition to the rock-solid core of leading men-cum-character actors in the most prominent roles), although it still boils down to a ‘what if?’ scenario. So flimsy in fact is the entire house of cards that the story ends – or rather comes to a halt (lacking, as noted above, a logical conclusion) – on a fallacious note: “Just because you can't prove it, doesn't mean it's not true.” It’d be a lot more reassuring if you could, though.