Zodiac is not just an excellent true-life drama, it also embodies a sensation of horror and a sense of mission.
"This case and the subject matter," says screenwriter James Vanderbilt, "attracts people who can be of an obsessive nature and that was a really interesting thing to examine."
Vanderbilt's comments are part of this week's stunning two-disc DVD. Zodiac: Director's Cut is a vast improvement on the version from last July.
But "director's cut" is misleading. Zodiac, already a methodical investigative procedural about California's infamous Zodiac serial killer, ran 157 minutes in theatres. Director David Fincher added five minutes, mostly in subtle tweaks.
One innovation is a 55-second sound montage of music and news that shows a time lapse from 1971 to 1975. The screen is black. The sequence is inserted just after San Francisco detective David Toschi (Mark Ruffalo) sees himself fictionized in Dirty Harry and then meets San Francisco Chronicle cartoonist Robert Graysmith (Jake Gyllenhaal).
Graysmith will become one of those obsessives and Zodiac is based on his books, Zodiac and Zodiac Unmasked.
The DVD extras are split between Fincher's obsessive filmmaking and the filmmaking team's obsessive interest in unearthing new information and putting old witnesses and policemen on camera. The approach is methodical, exacting, exhaustive and graphic (including victim photos).
There are two critical documentaries.
At 102 minutes, This is the Zodiac Speaking recreates four crime scenes and the resulting investigations.
The companion piece, at 43 minutes, is His Name Was Arthur Leigh Allen.
It cites Allen, who died in 1992, as the prime suspect. This powerful doc is equivalent to the trial and character execution that will never happen in life, or even in film.
