Since the arrival of cinema at the turn of the century, Hollywood has been fascinated with the dark side of human nature, a phenomenon clearly illustrated by the continuing popularity of serial-killer films in modern movies.

By exploring the horrific actions of individuals, these films have consistently aimed to seduce audiences with their depictions of both fictional and real-life cases. Zodiac, an example of the latter, takes an alternate approach to this subject, focusing almost exclusively on the perspective of those driven to put an end to one serial killer’s reign of terror.

Based on Robert Graysmith’s novel of the same title, Zodiac remains reverently true to its source material, delving into the details involved with the investigation. Chronicling the unraveling of the entire Zodiac case, the film takes place over 20 years, sporadically skipping ahead in time to the next crucial development in the hunt. While this approach certainly contributes to the film’s accurate depiction of the search for the Zodiac killer, the strict adherence to an accurate retelling of the investigation simultaneously serves as a drawback as well.

Since the case is routinely examined, dropped and then resumed by various individuals throughout the film, Zodiac constantly shifts focus from character to character, following whomever is actively pursuing the killer at any given time. Characters intermittently appear throughout the film, with some of the leads reduced to brief appearances in some instances.

As a result, Zodiac lacks a strong protagonist; the film is principally concerned with outlining the investigation itself, regardless of the negative effect this tactic has on the film’s storytelling.

However, despite its lack of a solitary hero, Zodiac offers strong performances by a trio of today’s most underrated actors. As the three men most affected by the hunt for the infamous Zodiac, Jake Gyllenhaal (Robert Graysmith), Mark Ruffalo (David Toschi) and Robert Downey Jr. (Paul Avery), offer complete and convincing portrayals of their characters as they become increasingly consumed with an overwhelming desire to discover the killer’s identity. Their devotion dissolves into obsession as the years fly by without an arrest for Zodiac’s crimes. Also, because each man becomes the focal point of the film at one point or another, they have plenty of opportunity to display their considerable acting chops; Downey in particular makes an impression as a sarcastic journalist hot on Zodiac’s trail.

Unlike most thrillers, Zodiac is not a cat-and-mouse game between a twisted genius and the moral do-gooder determined to bring him down. Rather, the film employs a faithful reenactment of one of modern crime’s most complex unsolved mysteries as a means to explore the nature of obsession. Although this approach results in a commendable effort to set Zodiac apart from the numerous predictable stabs at similar subject matter, its obsession with the facts causes the film to play more like a documentary of the Zodiac investigation than the big-budget popcorn flick audiences may expect.

Nevertheless, director David Fincher, the man behind classic thrillers such as Se7en and Fight Club does an admirable job maintaining the eerie and uncertain atmosphere necessary for a film such as this, and considering that Zodiac is principally about the relentless pursuit of truth, Fincher’s application of this method of crafting Zodiac is particularly fitting.