Trivia

• The cab scene on Washington and Cherry Streets in San Francisco could not be entirely shot in San Francisco due to filming restrictions and the opposition of the neighborhood residents. So, a set of the intersection, including the street, apartments and crime scene was constructed at Downey Studios just outside of Los Angeles, California. Backdrops of San Francisco were digitally inserted to complete the scene. Only a few seconds of actual footage shot in the original crime scene location remains in the scene.
• The Warner Bros. and Paramount logos used at the start of the film are almost identical to the ones used by the respective studios in 1969, with the most notable change being on the Paramount logo, where "A Gulf+Western company" now reads "A Viacom company", to better reflect Paramount's current status.
• Edited using Final Cut Pro
• Producer/Performer Anthony Begonia's parents were classmates of one of the Zodiac victims in San Francisco.
• The role of Linda Ferrin was initially played by Bijou Phillips. Her scenes needed to be re-shot but Phillips was not available due scheduling conflicts, so the role went to Clea DuVall.