For a brief period in the early '70s, the Zodiac killings transfixed the Bay Area, in large part because the killer used the media to hold the city hostage, forcing newspapers to run cryptic puzzles under the threat of further violence. But Zodiac, David Fincher's masterful procedural about the elusive case, resonates at least as much for depicting what happened in the years after the murders faded from the public consciousness. A sort of flipside to Fincher's Seven, which pulsed with the urgent need to catch a killer before he reached endgame, Zodiac is about what happens after a case goes cold and only a dedicated few remain to follow a trail that grows murkier by the day. An obsessive movie about the nature of obsession, it stays in perfect step with the men who chased these phantom leads, not so much because they felt some noble connection to the victims, but because they simply couldn't leave a puzzle unsolved.
Every bit the movie The Black Dahlia should have been—it comes as no surprise that Fincher was originally slated to bring that similarly infamous case to the screen—Zodiac follows the events in strict chronology, without imposing an artificial structure. This daring conceit risks shapelessness, but makes the passage of time more devastating, as datelines separated by days or weeks extend to full years while the case lies fallow. Not long after the Zodiac's first double murder on July 4, 1969, three men are drawn into the mystery: Robert Graysmith (Jake Gyllenhaal), an editorial cartoonist for the San Francisco Chronicle who would later write a bestseller on the killings; Paul Avery (Robert Downey, Jr.), a Chronicle reporter whose articles made him a Zodiac target; and hard-nosed homicide inspector David Toschi (Mark Ruffalo).
Zodiac has been billed as a departure for the notoriously detailed Fincher, mainly for taking a more subdued tone than previous thrillers like Fight Club and Panic Room, but it also feels like his most personal and accomplished work to date. Aside from Vertigo—forever the touchstone for obsessive Bayside thrillers—the film's nose-to-the-ground diligence most closely resembles All The President's Men, and it's no coincidence that David Shire provides the moody score for both. The key difference is that Zodiac isn't about an investigation into a crime that will powerfully affect the nation, it's about one that eventually loses all relevance to everyone but the few who can't let it go. Following these three men through countless dead ends and red herrings may sound like a perverse endeavor—though Fincher does at least break out one dazzling suspense setpiece—but Zodiac is the rare serial-killer movie in which the psychosis stems as much from the pursuers (and the filmmaker) as the pursued.