Playing Catch-Up: "Zodiac"

How do you craft a compelling thriller about an unsolved murder case? The approach chosen by director David Fincher and company in Zodiac was making the real subject the state of mind of the investigator: implicating us in his obsession, making his frustration the key to the movie's tone. Very impressive, and much less pummeling than the grimly methodical visual overstatement Fincher is known for.

The question that lingers for me is exactly why this case is still regarded as unsolved. What exactly is the distinction between circumstantial evidence and...whatever the other kind is? One of the investigators interviewed on the above-linked site says there are three ways to prove guilt: "An eye-witness, a confession or physical evidence." And this is apparently deemed to be so even when, as in the Zodiac case, a suspect is implicated by dozens of pieces of so-called circumstantial evidence that lock together in a way that couldn't possibly be accidental. (This is assuming that the cool objective manner of the movie isn't a snow job and that the evidence has been fairly summarized.)

A possibility the movie hints at is that the supposed suspect was an unusually subtle and crafty version of the cop movie old standby the false confessor, teasing the police and making himself the center of attention, expending considerable ingenuity to deliberately implicate himself, knowing full well that there was no direct evidence for anyone to find. There still seems to be enough left over, after everything is eliminated that might be susceptible to that kind of fabrication, but how much do you need for reasonable doubt? And with that I guess I've answered my own question.