After Zodiac's bus threat is released to the public, Robert is discussing "The Water Theory" in regards to how Zodiac chooses his victims (Lake Berryessa, Blue Rock Springs, Washington & Cherry.) The film's palette makes the color blue very prevalent in most of the scenes. Some examples include: Zodiac's letters are written in blue ink. The first is read by the editor who is wearing a blue shirt.When reading the decoded cypher, thus introducing Avery and Graysmith to each other, they are both wearing blue shirts.Robert is wearing a blue shirt in every scene he's in.In Morti's Graysmith introduces to Paul Avery a blue drink called an Aqua Velva. In the following shot with the multiple empty glasses the song "Crystal Blue Persuasion" by Tommy James & The Shondells.Melvin Belli's suit is navy with a light blue shirt.The woman who pulls over to help a Zodiac victim is wearing a blue jacket.Dave Toschi's suit is light blue when reading Zodiac's Halloween card.Paul Avery's shirt on the plane is blue.Arthur Leigh Allen's work coveralls are dark blue.When Robert is on the phone while his kids are going over his files, the shirt he wears and the phone are both blue.
In the scene where Graysmith decides to drive his son to school instead of letting him ride the bus, a 1971 Chrysler Newport can be seen parked at the curb behind the bus. The scene is set on October 1969.
What are the differences between the original version and the Director's Cut later released on DVD?
The directors cut offers five minutes of new plot scenes. Most of the news scenes are slightly extended dialogue sequences but there are also three new longer scenes. A detailed comparison can be found here.
Why does the movie not show the first confirmed Zodiac killing?
The movie claims to be based on "actual case files" and uses actual reports to construct the killings. In the Vallejo and Lake Berryessa attacks one of the victims survived to describe what happened. In the Paul Stine shooting witnesses saw the attack occur. In the first attack which can be conclusively attributed to the Zodiac, that of David Faraday and Betty Lou Jensen, there were no survivors or witnesses and so the film makers decided to not show the killing rather than try to reconstruct it based on forensic evidence. Robert Graysmith believes that in the Faraday/Jensen killing the Zodiac parked behind their car and approached as he did in the Ferrin/Mageau shooting. Faraday and Jensen appear to have been exiting the car and Graysmith believes that Zodiac shot Faraday first, after which Jensen tried to run and was shot.
Was the Zodiac killer ever caught?
No, he was not. There have been multiple suspects, but none have even been arrested. If he is still alive, it is believed he must be at least 60 years old. It is presumed that he is dead. The case is still officially open and is regarded as a "cold case". According to Wikipedia, the case was reopened again sometime before March of 2007.