From the establishing aerial shot of Vallejo, CA, and subsequent shooting of two teens parked in lovers’ lane (to the strains of Donovan’s “Hurdy Gurdy Man”), David Fincher invokes palpable dread and sustains it for nearly three hours. Refreshingly, he makes his focus not the serial murders of the Zodiac Killer who terrorized San Francisco in the late 1960s but the prolonged investigation, beset with dead ends, blind alleys, and dark nights for hotshot detective Dave Toschi (Mark Ruffalo), hard-drinking reporter Paul Avery (a standout Robert Downey Jr.), and obsessed San Francisco Chronicle cartoonist Robert Graysmith (Jake Gyllenhaal), whose book inspired James Vanderbilt’s meticulous screenplay. No procedural has better captured the unnerving limbo of unsolved crimes, or the tolls they take on the lives of dedicated crime fighters.