When Mills and Somerset go to Wild Bill's Leather Store to get information about John Doe (at about 1 hour 24 minutes into the film), the clerk says Doe "limps." Behind them, outside the shop, a limping man is seen watching the detectives.
Kevin Spacey makes his first appearance in the film as the photographer who takes photos of Brad Pitt and Morgan Freeman at the sloth murder scene. If you pause the film and look, in the scene where Pitt's character strikes the camera in the photographer's hand (around the 54th minute), it is clearly visible that the person wearing the wig is Kevin Spacey.
While Mills lists the things the killers gave as their reasons (around the 46th minute), he says, "Jodie Foster told me to do it." John Hinckley Jr., who was obsessed with Jodie Foster, attempted to assassinate President Ronald Reagan on March 30, 1981. Mills also says, "My dog told me to do it." David Berkowitz (also known as "Son of Sam"), the serial killer who terrorized New York in the summers of 1976 and 1977, claimed that his neighbor's dog had been possessed and told him to commit murder.
All the building numbers in the opening scene begin with 7. The delivery at the film's climax is set for 7:00 PM.
Although John Doe is one of the most terrifying and sadistic killers in cinema history, he is never seen killing anyone on screen.
In 2001, the Patriot Act gave the government the authority to monitor library records; at one point in the middle of the film, it is stated that this is certainly not legal.
In the scene before Mills and Somerset enter the District Attorney's office (around the 17th minute), the camera moves in on a newspaper announcing a murder. A small news item in the corner of the front page reads "Butler Held Hostage by Gerbil Seized by Child: Three Days of Terror," while another reads "Neighbor's Beagle Scares Youth, Cures 8-Year Hiccups."
David Fincher named the detectives in Fight Club (1999) after this film's screenwriter, Andrew Kevin Walker: Andrew, Kevin and Walker. Walker had done uncredited rewrites on Fight Club.
Mills's apartment is number 5A. The fifth deadly sin is wrath, the sin Mills commits at the film's climax. Throughout the film, he frequently reacts with irrational outbursts of anger to things such as the reading list Somerset sends or the photographer at the sloth murder scene; all of these are clues marking him as the victim of Wrath.
At exactly the seventh minute of the film, Mills receives a phone call that sets the seven murders in motion. At exactly seven minutes before the film ends, Somerset tells the devastated Mills about John Doe, "He'll win."
It was chosen by Entertainment Weekly as the eighth scariest film of all time.
Just before Detective Mills shoots John Doe (around the 2nd hour), a single frame of Tracy's face (1/24th of a second) appears. This brief moment may be why many viewers remember seeing Tracy's head in the box, even though the contents of the box are never shown on screen.
On the box full of photographs in the sloth scene (around the 53rd minute), the words "To the World, From Me" are written.
The metronome seen in one of the scenes is generally a symbol of patience, consistency and creating order out of chaos. It also marks the passage of time as Somerset waits.
Se7en set an interesting record when it became known through a popular electronic trivia system in the US: it became one of the most incorrectly answered questions in the system's history. The question was "In which city is Se7en set?" Most people answered New York, while the rest split among other Northeastern cities such as Boston and Philadelphia; only a few correctly knew that the film's setting is not specified.
In Orthodox Christianity, despair is counted as the eighth deadly sin; this fits Somerset's world-weary attitude toward life.
A remix of Nine Inch Nails' song "Closer" appears in the film but is not on the official soundtrack album. Trent Reznor later won an Oscar for the music of David Fincher's The Social Network (2010).
Andrew Kevin Walker named William Somerset after his favorite author, W. Somerset Maugham.
The seven deadly sins: Lust: To have an intense desire or need. "But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart" (Matthew 5:28). Gluttony: Excess in eating and drinking. "For drunkards and gluttons become poor, and drowsiness clothes them in rags" (Proverbs 23:21). Greed: An excessive or reprehensible desire to acquire. "Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, and they are full of greed" (Ephesians 4:19). Sloth: Reluctance to activity or exertion. "The way of the sluggard is blocked with thorns, but the path of the upright is a highway" (Proverbs 15:19). Wrath: Strong vengeful anger or indignation. "A gentle answer turns away wrath, but a harsh word stirs up anger" (Proverbs 15:1). Envy: Painful or resentful awareness of an advantage enjoyed by another, joined with a desire to possess the same advantage. "Therefore, rid yourselves of all malice and all deceit, hypocrisy, envy, and slander of every kind. Like newborn babies, crave pure spiritual milk, so that by it you may grow up in your salvation" (1 Peter 2:1-2). Pride: The state of being proud; excessive self-esteem. "Pride goes before destruction, a haughty spirit before a fall" (Proverbs 16:18).
In the film's opening credits (around the 4th minute), you can see John Doe cutting off his fingertips. This is later explained as the reason he can never leave fingerprints.
The film is included in Roger Ebert's "Great Movies" list.
Mills and William Somerset discuss the book "Of Human Bondage," written by W. Somerset Maugham (around 1 hour 7 minutes).
In the climax scene (around 1 hour 55 minutes), Somerset sees the box and runs back in horror; John Doe explains his final plan to him and Mills. In this scene, we see Mills go through the five stages of grief: Denial, Anger, Bargaining, Depression and Acceptance.
Throughout the film there are many references to decapitation, and this foreshadows the film's ending. Among them are the photographs in the books Somerset examines while researching the Seven Deadly Sins in the library, and the statue beside the upside-down painting at the Greed murder scene.
On Somerset's first visit to Mills's apartment (around the 36th minute), he sees a basketball on the mantelpiece. The tremor during dinner makes the ball fall (you can hear it drop and bounce on the floor). Shortly afterwards Mills picks the ball up and puts it back on the shelf; the next time a subway passes, it is certain to fall again. This is an early sign of his stubbornness and his refusal to accept the facts.
Although it is a serial killer film, the only murder shown on screen is committed by a police officer.
At the start of the film, the first shot of Tracy (around the 6th minute) shows mainly her head, partly concealed; this foreshadows her end.
The death toll is 9. This includes the first five victims of the Deadly Sins (assuming the Sloth victim dies shortly afterwards), Tracy and her unborn child, John Doe, and the murder victim Somerset investigated before meeting Mills. If the dead dog in the desert is counted too, it rises to 10.
Sloth is the third deadly sin; the Sloth victim is found in an apartment on the third floor.
An early scene in the film (around the 24th minute) foreshadows the ending. As Somerset lists the Seven Deadly Sins for the first time at the police station, he pauses at the last Sin and, turning to Mills, says "...and envy."
John Doe is seen entering the diner where Somerset and Tracy meet and taking off his hat. This is how he learns what Tracy told the detective.
The murder Somerset investigates at the start of the film foreshadows the finale. Both can be described as "crimes of passion."
Although John Doe is referred to throughout the film and in cinema history as a "serial killer," he actually kills only three people himself: he forces the obese man (gluttony) to eat and kicks him until his stomach bursts; he kills Tracy and her unborn baby by cutting off her head. Although he is directly responsible for the other deaths, they do not come by his hand: the lawyer (greed) cuts himself under threat and bleeds to death; the prostitute (lust) is killed unwillingly by a client; the model (pride) commits suicide rather than remain disfigured; the Sloth victim is kept alive at great expense, but does not live long; Envy (John Doe himself) is shot by Detective Mills; and the victim of Wrath is the surviving Detective Mills. So technically, John Doe personally kills only one victim for his sins. He also killed Tracy and her baby himself, but not because of a sin they committed.
As Mills and Somerset search John Doe's apartment, look carefully at the Wild Bill's Leather Shop receipt. The handwriting in the description reads "CUSTOM LEATHER." The "C" in "Custom" can be read as an "L." If you freeze that moment, it reads "Lust." This is a reference to the next crimes Doe will commit relating to the seven deadly sins.
While having a drink in a bar after finding the lust victim, Somerset tells Mills, "You know, this isn't going to have a happy ending," pointing to the film's climax.
In the car scene with Mills, Somerset and John Doe, Mills is shot behind bars; this foreshadows where he will end up.
In the film's opening credits, John Doe is seen blacking out printed words on a page with a black pen. The text begins with "While pregnant" and points to Tracy's pregnancy.
It is not clear which state the story takes place in, because at the end of the film, when Somerset opens the box containing Tracy's head, he says into the radio to the helicopter, "California, stay away from here!" California is the name of the SWAT team leader played by John C. McGinley.
Just before John Doe surrenders at the police station, Somerset tells Mills, "Either we catch John Doe or he completes his series of seven and this case drags on for years." Apart from the case dragging on for years, that is exactly what happens at the end of the film.