Then, I put in disc 2 from the ZODIAC DVD set. It is CRAMMED full of information about both the making of the film (almost an hour long documentary) and in a separate section, interviews with all five of the Zodiac killer's crime investigators and survivors. That part of the bonus has already run 90 minutes, and I'm still watching it, though it has gotten to the last murder (the cab driver), so I'm thinking it doesn't have much more to run.
The movie has eeriely captured the look and feel of the period and the people which, apart from how well it's directed, makes it seem so memorable.