'Zodiac' warms up a cold case

Movies about obsessions can be wearying, especially if the obsession remains unchecked. Such would appear to be the case with "Zodiac," which is about the notorious, never-solved San Francisco serial killings. But the film turns out to be an engrossing 2-1/2-hour ride – part police procedural, part bogeyman thriller, part crime blotter version of "All the President's Men."

Director David Fincher is not known for his light touch. His most egregious film, "Se7en," – that-slash and-burn thrill ride – was also, alas, highly influential; so was "Fight Club." He gives an artsy patina to pap.

In "Zodiac," working from a script by James Vanderbilt, he has decidedly toned down his act. His straight-ahead, methodical direction isn't as flagrantly unsettling as much of his previous work, but it's more psychologically layered. In this film, for the first time, we feel for his characters when they bleed.

The film begins July 4, 1969, when the Zodiac killer – whom we see only as a hulking, masked marauder – shoots two teenagers in a lovers lane. A month later he sends ciphers to three San Francisco papers, threatening to kill again unless they are published.

He kills again, of course, this time a couple near a secluded lakeside picnic spot in Napa Valley. The murder is easily the movie's most graphic, and there's a good reason for this: By impressing on us the horror of these killings, Fincher thankfully does not need to up the ante any further as he racks up the body count.

The cast of characters is sprawling and diverse. Paul Avery (Robert Downey Jr.) is the San Francisco Chronicle crime reporter who becomes increasingly pulled into the case. With his goatee and scarves, he's like a fop inquisitor – until eventually, the grind of the investigation unravels him. The Chronicle's cartoonist, Robert Graysmith (Jake Gyllenhaal), is an amateur sleuth who, as the years tick by without an arrest, becomes as obsessed as Avery. Sacrificing his family life and his job, he sets out to write a book about the hunt for the killer and even offers up a solution. (His bestselling book is the basis for the screenplay.)

The third major player in "Zodiac" is homicide inspector Dave Toschi (Mark Ruffalo), who enters the picture once the Zodiac killings begin in San Francisco. Although Toschi in real life was the basis for both the Steve McQueen character in "Bullitt" and Michael Douglas's cop in "The Streets of San Francisco," Ruffalo wisely tamps down the showboaty side of this man. Ultimately, he is as beleaguered by everyone else by the cold trails and dead ends, of which we see plenty.

The doggedness of the pursuit, the painstaking accumulation of clues, has its own inherent drama. Much of "Zodiac" involves people jabbering at each other rather than running around with guns. The real violence, especially once the film moves into its second hour, is emotional, not physical.

The excellent cast also includes Brian Cox as publicity hound attorney Melvin Belli, John Carrol Lynch as a prime suspect, Charles Fleischer as the suspect's creepy associate, and Philip Baker Hall as a besotted handwriting expert. They all give human weight to a grisly odyssey. Grade: A–

• Rated R for some strong killings, language, drug material, and brief sexual images.