"I believe this is a window into this man's soul. Killing is his compulsion. Even though he tries to ignore it, it drives him. It's in his blood."
"Could be, or maybe he just likes the attention."
Zodiac is a 2007 film directed by David Fincher, chronicling the killings of the mysterious California killer known as Zodiac, as well as the people who tried to uncover his identity. The film focuses on three main characters:
Robert Graysmith (Jake Gyllenhaal) a cartoonist for the San Francisco Chronicle who becomes obsessed with the Zodiac.
David Toschi (Mark Ruffalo) a renowned San Francisco homicide detective who is put on the case indefinitely.
The main problem catching the killer is that none of the agencies and jurisdictions investigatingnote Vallejo PD, SFPD, Napa County Sheriff, Solano County Sheriff and California DOJ have all of the same information, and often the evidence seems to contradict itself. Robert Graysmith eventually takes it upon himself to go between them and solve the crimes.
Zodiac provides examples of the following tropes:
Adult Fear: Graysmith starts out fearing for the life of his children, including pulling one off a bus after Zodiac threatens to shoot out a school bus. Later subverted when he continues his investigation despite receiving threatening calls to his house and, in a darkly humorous moment, involving his grade-school age kids in the investigation.
Attention Whore: The Zodiac; he sends letters to the police and media bragging about his kills, including taking credit for murders that may not have been his. Melvin Belli and Paul Avery have shades of this too.
Beat Panel: 1983, when Robert and Leigh meet face to face. Even though nothing is said, it's clear that both know who the other is.
Bittersweet Ending: While Robert gets off pretty well (you can see that he wrote a book about the Zodiac experiences on the Bestseller rack in a bookstore), Paul ends up becoming a stoner and there is the undeniable fact that the KILLER FUCKING GETS AWAY.
Bound and Gagged: Zodiac's 3rd set of victims (his second on-screen set) end up like this.
Call Back: Robert states he won't be able to stop investigating the case until he's able to look the killer in the eye. He does just that when he meets Arthur in the hardware store at the end.
Cast as a Mask: The titular killer is played by 3 different actors (John Lacy, Richmond Arquette, and Bob Stephenson), while the two suspects, Bob Vaughn and Arthur Leigh Allen are played by Charles Fleischer and John Carroll Lynch, respectively.
Distant Finale: The last scene takes place in 1991, 8 years after Graysmith finds Leigh at the hardware store. The only person to see the Zodiac without a mask is taken in to see some photographs. He points out the one of Leigh, with an 8 out of 10 assuredness.
Downer Ending: While Robert gets off pretty well (you can see that he wrote a book about the Zodiac experiences on the Bestseller rack in a bookstore), Paul ends up becoming a stoner and dies, Allen dies before his guilt can be proven or disproven, and there is the undeniable fact that the KILLER FUCKING GETS AWAY
Politically Correct History: Averted: 'negro' is used interchangeably with 'black' in the 60s and 70s, and "retard" and "homosexual" are used as insults.
Put on a Bus: Michael Mageau, one of the first on-screen victims and the only person to see Zodiac without a mask, skips town as soon as he gets out of the hospital.
The Bus Came Back: He returns at the very end of the movie, and positively identifies Allen as his shooter.
Red Herring: Rick Marshall manages to take up thirty minutes of the movie despite never being seen and not being Zodiac. We think.
The Riverside killing. And the attack on the woman on the highway.
Many of the Zodiac's letters only repeat information already published in the newspaper, leading investigators to think he's just taking credit for crimes he didn't commit.
Room Full of Crazy: Rare heroic example; by the end, Robert's house has been taken over by boxes of files related to the Zodiac.
Sssssnake Talk: "Thisssssss issssss the Zzzzzzzzzodiac ssssssssspeaking..."
San Francisco: Shown in all its glory, mercifully free of the usual stereotypes.
Sanity Slippage: Graysmith. He goes from a fairly stable if some oddball cartoonist and loving father, to a one-man investigative team trying to solve the Zodiac murder, quitting his job and driving his own family in the process. It's not until the end, when he's able to look Arthur Leigh Allen - the person he believes to be the Zodiac - in the face that he's able to recover. Apparently this was Truth in Television for the real Graysmith.
Scenery Porn: The opening shot of the North Bay on the fourth of July, the sweeping view of San Francisco's waterfront, the skyline at Christmas, the Napa Valley, the interminable darkness of the Central Valley at night...
Second-Hand Storytelling: The first known murder committed by the Zodiac killer isn't shown in the film due to there being no surviving witnesses. The murder of Cherri Jo Bates also talked about but not shown again due to lack of survivors and due to it happening three years prior to the start of the film.
When the Zodiac threatens Paul Avery, everyone begins to wear "I am not Paul Avery" buttons, including Paul Avery.
And when Leigh is being interviewed by police:
Leigh: (to police officers) Those knifes with blood on them were from a chicken I killed.
Leigh: (to police officers) I'm not the Zodiac, and if I was, I certainly wouldn't tell you.
The End... Or Is It?: Graysmith is positive he's found the killer, and Fincher clearly agrees that it's a very convincing case, but the film very deliberately leaves it open that they might be wrong. John Carrol Lynch plays the assumed killer as just another guy annoyed at being bothered by the police, so you don't judge him as evil simply because he acts evil: you have to decide based on the available facts. Does the evidence stack up or doesn't it?
Unperson: Darla's sister seems to drop off the face of the Earth when Graysmith is looking for her. He eventually finds her in a prison.
Mike Mageau, the only person to see Zodiac without his mask and live, skips town once he's out of the hospital. He comes back at the very end, 22 years after the shooting.
Unreliable Expositor: Sherwood? Who was fired from Questioned Documents? Who drinks like Paul Avery?
The Unsolved Mystery: SFPD has officially closed its Zodiac homicide investigation, despite the fact the 1969 case remains unsolved and leads continue to pour in.
Very Loosely Based on a True Story: Surprisingly, averted: at Fincher's insistence, the film was meticulously researched for historical accuracy, with the cast and crew consulting with nearly every living person who was involved with the case, including the two surviving victims.
Dated History: Of course some things in the film have been proven incorrect, as new evidence has came to light in the years since the film's release. For example. in the film Zodiac is shown sitting in the backseat of the cab before killing Paul Stine, while in real life, there was evidence that he actually sat in the passenger seat next to Stine. Also, Arthur Leigh Allen hasn't been suspected of being the Zodiac for many years; these days writer Richard Gaikowski is the main suspect.
We Need to Get Proof: The main challenge once the heroes become convinced that Leigh is the Zodiac. Despite mountains of evidence — the windbreakers, the gloves, the wing-walker boots, the knives, the guns, The Most Dangerous Game, the watch - it could all be dismissed in court as circumstantial.
"Where Are They Now?" Epilogue: Graysmith is happy with his children, Leigh died of a heart attack before the police could charge him with the murders, and Paul Avery died around 2000.