"Human nature is violent," William Friedkin tells me, going on to say that he also likes Immanuel Kant's phrase "the crooked timber of humanity." As an artist, Friedkin is as blunt, matter-of-fact, and masterfully cynical as his initial statement suggests. His films indicate that a character's environment is, more often than not, what he reacts to when he snaps. Superior dramas like The French Connection (1971), To Live and Die in LA (1985), Cruising (1980), and Sorcerer (1977) are all about myopic obsessives, characters who are desperate to the point where they can't see how their actions have led them to become fatalistically self-involved. That same tendency towards self-harm is what makes many of Friedkin's movies bleakly and corrosively funny. For example, the hanky code scene in Cruising, where Al Pacino's undercover cop is comically baffled by the semiotics of the hanky code, is humorous because we're being encouraged to laugh as a man denies his own latent attraction to the subcultures he's investigating. 

So in that sense, it's not surprising that Killer Joe (2011), which Friedkin describes as his "darkest film yet," is a comedy. In it, Matthew McConaughey plays a corrupt, schizoid cop hired by desperate white trash to kill one of their own kin in order to collect a $50,000 life insurance policy. "Yes, it's a black comedy, in the way that Dr. Strangelove is a black comedy, nonetheless disturbing because of its subject matter," Friedkin told me Wednesday. He went on to tell me that with Killer Joe, he wanted to make a dark comedy that was direct and brutally "unsentimental." You can see that lack of sentimentality in the way that Friedkin uses Clarence Carter's "Strokin,'" a song that is about exactly what it sounds like what it's about, twice in Killer Joe. "I love 'Strokin'!' I think it's very funny and courageous. It's sort of a character on its own. It's kind of a statement on the all of the bullshit that surrounds today's films, kind of a reaction to that. It's not sentimental and the movie is not sentimental. It's funny, and if you really listen to it, it's a little dark." 

It actually makes sense that "Strokin'" is used during a scene in which a major character gets beaten to a pulp, a nasty choice but not excessive to the point of being gratuitous. For a filmmaker who has, over the years, continually pushed the envelope in his portrayal of violence on film, especially in films like The Exorcist (1973) and Cruising, that's saying a lot. "I thought I went as far as I needed to and no more or no less," Friedkin remarked.  He went on to say that he and his crew were surprised that the film got an NC-17 rating, in spite of its handful of scenes of full frontal nudity and over-the-top violence. Despite his surprise, Friedkin does not contest the rating: "None of us thought we'd get an NC-17, but when we did, I think we realized it's the correct rating. Because I'm not targeting teenagers. Once I got that rating, I knew I could hack that movie to pieces to get an R, but I didn't want to do that. I just didn't want to do that. So once they gave us an NC-17, the distribution company appealed it and they lost the appeal. So we left it alone."

Violence and sex are often the source of dark humor in Friedkin's films, a debt traceable to Friedkin's affinity for Henri-Georges Clouzot's films. Many of Clouzot's movies, like The Murderer Lives at Number 21 (1942) and Le Corbeau (1943) have a vicious sense of humor and are character-based. In fact, Friedkin's Sorcerer is a remake of Clouzot's Wages of Fear (1953), a masterful thriller about a group of broke truckers who go on a suicide mission to deliver highly unstable dynamite to a construction site deep in a South American forest. Friedkin has said in the most recent issue of Film Comment that he'd probably seen Clouzot's Diabolique upwards of 50 times, but he would never consider remaking it. "I love Clouzot's films," Friedkin beamed. "They're hard-edged and they're not sentimental. Diabolique is a very scary film. That nine minute sequence, without a word, is one of the most terrifying scenes I've ever seen."

But what makes Friedkin's films so unique is that sense of acidic humor stems from a perceptive view of the apathetic environments that breed his characters' obsessive and often inexplicable behavior. For example, in Rampage (1987), Friedkin follows the trial of a disturbed mass murderer shown to have Nazi paraphrenalia in his room, which is situated in the root cellar of a house ostensibly presided over by Twin Peaks star Grace Zabriskie. Both the defense seeking to prove that Zabriskie's son is legally insane and hence not in control of his actions, and the prosecuting attorneys who try to prove the defendant's guilt, produce evidence and witnesses that support their claims, leaving it up to the viewer to decide who is right and which factors matter most. 

Similarly, the abrupt demise of the corrupt cop William Petersen (of CSI and Manhunter) plays in Friedkin's To Live and Die in LA is not that shocking, given the context of the drama preceding his death. Petersen plays a character so myopically focused on arresting the counterfeiter responsible for the death of his partner that he can't see anything else around him, not even the vibrant Los Angeles that Friedkin practically makes a central protagonist of his story. "A lot of people found [the death of Petersen's character] shocking at the time, just as they found the death of Janet Leigh shocking in Psycho," Friedkin protested. But at the same time, it's only immediately jarring. Thematically, that violent death is hardly gratuitous.

That same focus on the ways environment and setting shape a character's identity is true of Cruising, a film possibly even more notorious than The Exorcist. In it, Pacino plays an undercover cop who descends from a position of feeling above-it-all—though reluctant to fully embrace the almost god-like, condescending perspective that comes with being a cop—into a struggle to repress latent feelings of homosexuality when he goes in search of a killer in the Meatpacking District’s S&M Clubs. The self-loathing mania that defines Pacino's character has been unfairly called a sign that Friedkin considers homosexuality an abnormal disease, but his character's actions tell a different story when looked at in context. For example, a pair of cops on patrol deliberately paraphrase Taxi Driver's Travis Bickle when they say, "Some day, a rain's going to come to wash all the scum off the streets." Friedkin says he remembered "overhearing that dialogue from cops that were patrolling the Meatpacking District, as it was then. That district is now completely gentrified. But that's the way cops talk. That's the attitude: all these people on the street, they're scum!" 

Friedkin went on to add that Randy Jurgenson, a NYC beat cop who worked with Friedkin on three films, including The French Connection, and was the main source of inspiration for Pacino's character in Cruising, didn't need to explicitly tell him how his undercover search affected his psyche. "[Randy] sort of resembled the victims, who were all dark-haired, with swarthy complexions and mustaches," Friedkin remarked. "And he was about the same height and the same build and he was assigned to attract the killer. And he told me his experiences and how the whole thing really screwed him up and bent his mind. And I remember never asking him further what he meant; I got it! "

The impotence and sociopathic feelings of powerlessness motivating characters like Pacino's character in Cruising and even McConaughey's in Killer Joe are crucial to what makes Friedkin's films so rich and also rather ugly. They have a pragmatic despair at their hearts because, to Friedkin, human behavior is gross and uncontrollable. When I asked him why he thought people were grasping at straws to qualify the "evil" motives behind the recent killings in Aurora, Colorado, Friedkin exclaimed, "Because there's no way to control human behavior, not even in China, where they basically have a dictatorship. And they have no ethnic differences whatsoever, no color differences. The reason why China has made such leaps forward economically is because they can control human behavior and punish it severely if it's at odds with the norm. In this country, we don't. We cannot control the norm. In this country, when you have democracy, there's nothing you can do to modify people's behavior." 

With that in mind, Friedkin's films appropriately function as Rorshach ink blot tests for viewer reactions. For example, the ending of The Exorcist comes after an exhaustive battle for the soul of a young child. That battle is eventually, though hardly inevitably, won, after one priest forcibly defenestrates himself. The calm following this cure is uneasy, at best, making it very easy for viewers to see what they want in that calm after the storm. "The ending of The Exorcist is in the mind of the beholder," Friedkin told me. "What you take from the film is what you bring to it. If you think the world is a dark and evil place, that’s what you will get back. If you think there is hope for a power of the good that is constantly at war with the power of evil, you'll get that."

Simon Abrams is a New York-based freelance arts critic. His film reviews and features have been featured in The Village Voice, Time Out New York, Slant Magazine, The L Magazine, The New York Press and Time Out Chicago. He currently writes TV criticism for The Onion AV Club and is a contributing writer at the Comics Journal. His writings on film are collected at the blog, Extended Cut.