David Fincher, director of many dark bedtime stories (Se7en, Fight Club), returns with Zodiac, a film about the infamously unsolved hunt for a Californian killer. The film is based on the best-selling book by Robert Graysmith, who worked for The San Francisco Chronicle during the “Zodiac” years.

A surprisingly solid cast backs up the story. Though the casting choices of Mark Ruffalo as hardened detective Dave Toschi, and cherubic Jake Gyllenhaal as Graysmith are a bit unnerving at first, both actors effectively convey the frustration and passion that surrounded Zodiac’s reign. Especially impressive is Robert Downey, Jr.’s portrayal of Paul Avery; Downey seems to truly connect with his character.

The film’s only major flaw is that the audience starts to feel its length as it pushes past the two-and-a half hour mark. Perhaps Fincher chose such a lengthy cut to echo Graysmith and company’s fruitless and unyielding efforts to capture the murderer. Fincher’s Zodiac is, at turns, a frightening, witty and disturbingly comical probe into the minds that hunted the killer.