Zodiac ending explained · Cinespective

What happens

Graysmith finds Arthur Leigh Allen working in a hardware store, and the two men exchange a long, silent look. On-screen text then says Allen died in 1992, was never charged, and that the case remains unsolved.

The last image

Graysmith and Allen look at each other across the hardware store, and the film cuts away without a word being said.

Two readings

1 · Graysmith is certainThe look is where he becomes convinced, and the film lets you feel that conviction.

2 · Certainty isn't proofA look proves nothing, and the closing text reminds you Allen was never charged.

What it says

The film is about the hunger for certainty, so it gives you conviction without closure. It ends on what a look can and can't prove, because that gap is what the whole case, and Graysmith's obsession, has been about.