Warning: Spoilers below

A legend of horror cinema, director Dario Argento’s most famous film might be Suspiria, but he made his name in giallo, Italy’s pulp thriller genre. His 1982 film Tenebrae was more than just a return to the classic giallo themes of serial killers and detectives – it was born of a terrifying encounter with a deranged “fan” that inspired Argento to make his best thriller. In Tenebrae, American crime novelist Peter Neal (Anthony Franciosa) travels to Rome for a book tour whilst a serial killer is on the loose. The murders are clearly inspired by Neal’s work and, when he starts getting letters from the killer, the writer turns amateur detective. It’s a classic set-up for a giallo – the word means “yellow,” the color of the covers of the cheap Italian detective novels that started the genre. While giallo films had been popular since Mario Bava’s 1963 The Girl Who Knew Too Much (as the title suggests, Alfred Hitchcock’s influence looms large in the form), in the 1970s Argento took the genre to new heights of style and explicit violence in films such as The Bird with the Crystal Plumage and Deep Red.

After the release of the supernatural horrors Suspiria and Inferno, Argento was staying in a Los Angeles hotel when he received a series of unnerving phone calls. As recounted in the director’s autobiography, Fear, the unidentified caller was initially quite engaging and clearly very knowledgeable about his films. Argento took him for an avid fan or “some kind of madcap journalist.” However, things took a very dark turn when the caller started referring to himself as “The Great Punisher.” The police got involved and the caller abruptly ceased contact, but not before a promise that the best day of his life would be when he killed Argento. While the filmmaker found the incident terrifying, it also inspired him to start writing a giallo about an insane fan, originally titled Under the Eyes of a Killer. It was the story that would become Tenebrae.

The parallels between Argento’s real life experience and the plot of the film are only too apparent. Like Argento, Peter Neal is a giallo specialist (albeit as a novelist) whose latest book is also called Tenebrae. During the film Neal is attacked by critics who claim that his books are sadistic and misogynistic, one of whom is simultaneously knowledgeable about and repulsed by the material. This critic, Christiano Berti (John Steiner), is ultimately revealed to be a killer. He’s on a puritanical mission to purge “human perversion” from the city through murder. In a series of anonymous letters delivered to Neal’s hotel room, Berti calls the author “The Great Corrupter” and in one scene stuffs pages of his book into a victim’s mouth. Berti is clearly an echo of “The Great Punisher,” but he’s also a classic giallo killer – owning a secret basement where he develops photographs of his kills and a workbench covered with cut-up letters for poison pen mail. Argento’s films lovingly focus on the minutiae of a killer’s work, particularly the rituals and skills. Was this how he had imagined his own tormentor?

In earlier giallo, Argento had taken the form to new levels. The Bird with the Crystal Plumage opens with a stunning murder sequence that plays tricks on audience perception. Four Flies on Grey Velvet features a credulity-stretching plot device (a scientific procedure that scans the last image from a dead person’s retina) to reveal the killer. In Tenebrae, Argento further plays with the form that he had helped develop. The first half of the movie sets up the type of giallo audiences expected from the director, featuring a killer driven by sexual obsession (masked as ultra-conservative disgust). His elaborate murders employ the usual fetish elements, including black gloves and a straight razor. However, this psychopath is dispatched midway and replaced by a second murderer who kills more crudely with an axe.

Giallo protagonists often turn amateur sleuth to find a killer and clear themselves of wrongdoing. Here Argento sets Neal up as just such a lead, although he’s ultimately revealed as the second psychopath. The two-killer plot device cleverly diverts suspicion from Neal as the first murder occurs in Rome before his plane lands. Neal’s later sleuthing is a disguised attempt to take the place of the killer and set up a revenge plot on his agent, Bullmer (John Saxon), who is having an affair with his ex-lover (Veronica Lario). It’s not uncommon for giallo to have labyrinthine plots, but Tenebrae goes one step further in wrong-footing the audience. Neal is a stand-in for Argento by virtue of his profession and the way he is attacked for his material, but the director also examines the role of director as manipulator.

Neal eventually mocks the lead detective (who admits he never guesses the murderer in giallo), saying that he had worked out the identity of the killer very easily and planned his own set of murders “like a book.” As a reflection of the director, Neal shares a love of artifice and game-playing that mirrors Argento’s highly stylized approach. Tenebrae features one of Argento’s most technically brilliant scenes – a continuous shot around the outside of a house as Berti kills two victims. A later scene, where the soon-to-be-killed Bullmer watches people around him, knowingly references the voyeurism of Hitchcock’s Rear Window.

Tenebrae keeps with a theme of doubling throughout the movie. There are two killers and two sets of murders with different motives. Many of the characters have doubles, or are mistaken for one another at key points. When Neal thinks he’s killed his personal assistant (Daria Nicolodi) in the film’s final massacre, it turns out to be a female detective (Carola Stagnaro). Neal’s own double is Detective Giermani (Giuliano Gemma) and, after a fake suicide, he appears directly behind him – literally taking his place when Giermani kneels down out of the frame. Just as the figures of “The Great Punisher” and Argento himself are mirrored in the film, so too are other characters and structure, which is divided when Neal kills Berti and takes up the slaughter.

Along with its violence and conventions, giallo is one of the most playful of genres – stylish and deliberately artificial. Argento is a master of the form and Tenebrae represents him at his most inventive. He was clearly inspired by his stalker, but he's also speaking to his more conventional critics in the film. In his autobiography he describes Tenebrae as "a little bit of revenge" on the critics who regularly attacked the violence in his movies. Ironically he does this by doubling down on the explicit content. Set mostly in daylight and starkly lit modernist apartments, Tenebrae's brightness all leads up to an explosion of blood against a white wall in Neal's most brutal kill. Tenebrae means "darkness" in Italian, but Argento's film is all about the inner shadows of his characters, as he reiterates in his autobiography. It can also refer to a church service that takes place in increasing darkness (by extinguishing candles) until the gloom is pierced by a loud noise (the "strepitus"). Argento's film is marked by growing darkness, right up to its bloodbath of an ending, which is capped by a piercing scream in the final moment. Take that, critics!

Argento never found out the identity of "The Great Punisher" and it's clear from his book that he was only too glad the disturbing individual simply disappeared. Tenebrae is the legacy of that moment, easily the director's best film of the 80s – although 1987's Opera (another story about a murderous fan) comes close. It's also Argento's statement to his critics that he wouldn't back down, producing a film that surpasses his previous peak giallo, Deep Red. For fans of cinematic thrillers and killers, or just horror in general, Tenebrae remains an unmissable treat. Just don't love it too much.

from https://collider.com/dario-argento-tenebrae-inspired-by-his-stalker-explained/