Zodiac

Zodiac is widely regarded as one of the most meticulously researched true-crime films ever made, with screenwriter James Vanderbilt and producer Mike Medavoy consulting original police files, FBI documents, and interviews with surviving investigators Robert Graysmith and Dave Toschi. Fincher famously insisted on recreating crime scenes using actual forensic photographs. Some composite characters and timelines were condensed, but the core procedural details are faithful to the historical record.

The film focuses primarily on Arthur Leigh Allen, who was investigated extensively by the Vallejo Police Department and named as the prime suspect by Inspector Dave Toschi, though DNA evidence in later years was inconclusive. Other real-world suspects included Rick Marshall and Lawrence Kane. The Zodiac Killer was never officially identified or apprehended, and the case remains open.

Zodiac has a runtime of approximately 157 minutes in its theatrical cut, with the director's cut extending to about 162 minutes. Fincher's deliberately slow pacing mirrors the real decades-long investigation, deliberately contrasting with conventional serial-killer thrillers that escalate toward a neat resolution. The film's structure follows the obsessive toll the unsolved case took on cartoonist Robert Graysmith, reporter Paul Avery, and Inspector Dave Toschi over many years.

Between 1969 and 1974, the Zodiac sent at least four cryptograms (ciphers) to the San Francisco Chronicle, San Francisco Examiner, and Vallejo Times-Herald, along with taunting letters claiming responsibility for the killings. The infamous 340-character cipher was not decoded until December 2020, when an international team of codebreakers cracked it—more than 51 years after it was sent. The film accurately depicts the initial decoding of the simpler 408-character cipher.