Matt: There's a quote in Graysmith's book The Zodiac that jumped out at me: "Of the 2500 Zodiac suspects, only one remains that excites the investigators' interest and my own. Bob Hall Starr, the ‘gut-feeling choice’ of most detectives. Nobody knows who Zodiac is, but based on the evidence I have seen, Starr is the best choice by far."

I think that last sentence sums up the film's approach for me. The part before the first comma is Fincher. The rest of the sentence is the film's hero, Graysmith.

Those two parts can coexist in a work of art. But I think the first part—the fact that we just don't know who the Zodiac was -- takes precedence onscreen.

That's what I was left with.

Mike: By definition, then, Matt, there's no way any film about the Zodiac could be anything but ambiguous.

Matt: Not if it's being honest, no. Otherwise you end up with something like that second How-Truman-Capote-wrote-In Cold Blood movie, where Capote is having an affair with Perry Smith behind bars, or that horrible Hitchcock, where the director is hallucinating encounters with Ed Gein. And I think Zodiac is honest.

Sarah: Do we know much about the film’s investigation of various witnesses etc.? Graysmith refers to it in an interview, that Fincher had his own P.I. team trying to find Mageau, I think?

Matt: Fincher did invest a lot into sort of re-investigating the case. Supposedly he spent a year and a half in the lead-up.

Mike: I feel like they dug something up, because "at least an eight" (Mageau's answer about how sure he feels on a scale of one to 10) isn't in Graysmith’s follow-up to Zodiac, Zodiac Unmasked. I thought it was, but upon checking found that I was wrong. And I doubt they would make that up. So they talked to somebody.

I'd be curious to know if anyone asked Fincher for his opinion about whether Allen was the Zodiac, if he has one. The end of the film really makes me feel like he wound up buying into Graysmith's argument.

I just feel like there are an infinite number of ways Fincher could have ended the film on a note of uncertainty that would be more effective than "I'm very sure that's the man who shot me."

Matt: I feel like the ending says that Fincher wanted to buy it -- any artist empathizing with his subject would want that! -- but he stopped just short.

Sarah: Or that the movie was already nearly three hours long, and trying to explain why another suspect is a better bet is going to push the shit into Shoah territory.

Matt: A nine-hour version of Zodiac. Some people would really dig that, I bet.

Sarah: I'd watch it. Zodiacholas Zodiackleby.