HOMOSEXUALS writhe in William Friedkin's sick vision of hell on Christopher St. like hairy, sweaty messengers of Satan, grinding in a torturous dance of violent, evil sex. Come with me, Friedkin beckons, across Christopher St., a tartopped Styx, through a black door marked "private club." Follow me down a stony stairway into a savage den of black leather jackets, tight jeans, shiny boots, studded belts, heaving chests, tank tops, naked torsos, bulging muscles, captain's caps, jock straps, weird tattoos, mirrored sunglasses and gold necklaces strung so tight no one breathes.

Don't go with him. Don't go anywhere Friedkin points his leering, luring camera. Cruising purports to tell the story of a young New York cop, immersed in the frightening S-M-leather world on Christopher St., who confronts his own homosexuality. Instead, it is a look at that world through the crossed eyes of a man who sees homosexuals as masochistic, narcissistic, immature, seemingly crazed men. Friedkin considers homosexuality the wrong, evil side of everyman's sexuality, the sexual demon that must be exorcised for man to return to the normal, clean love of a woman.

Cruising horrifies from the start. Explicit killing supersedes explicit homosexuality on the screen. The killer cruises a victim--picks him up--in a hellish bar and they move on to a sleazy hotel. There, the victim admires his sleek, naked body in a mirror, flexing his muscles while the killer, visible in the mirror, lurks in a shadowy corner. The mirror dominates these men, Friedkin implies. They are narcissistic; they love themselves and they love physical replicas of themselves, mirror images.

The killer binds his victim with a leather strap, unsheathes a shiny butcher's knife, then plunges it unmercifully into the victim's back. Murderous entry is from behind, the tool is cold, sharp-edged, violent and unrelenting. The victim emits no sound, too shocked by his fate and caught in the grip of Friedkin's version of the S-M homosexual's ultimate pleasure--death.

Al Pacino plays the cop summoned for undercover work along Christopher St. because he looks remarkably like all the victims of the "Homo Killer" and might attract him. "Have you ever had your cock sucked by a man?" detective Captain Paul Sorvino asks. "Huh?" responds Pacino. "You gotta be kiddin." But no one is kidding and Pacino takes the assignment for the chance to skip patrol duty and the opportunity to nab a gold detective's badge.

Pacino trundles Serpico-style to Greenwich Village and sets up shop. He spends days with his nextdoor neighbor, Ted (Don Scardino), a gay playwright ("you know, boy meets boy, boy loses boy, boy gets analyst") who is scared to death of cruising, preferring to frequent more traditional gay cafes that Friedkin never shows. Nights, Pacino cruises, donning his leather outfit like a pudgy boy pulling on his first Halloween costume. Later, of course, the leather will no longer be a costume and Pacino will stop fumbling with the cruising paraphernalia. He will fit into the crowd in that hole across the Styx, and while he can't prevent two more stabbings (both from behind) he gets better at his work.

The movie builds from its bloody beginning, cutting between Pacino's encounters with the S-M crowd, his growing relationship with Ted ("I wish I could do something for you," Al mysteriously tells his cute, freckled neighbor) and his visits to his girlfriend (Karen Allen). The driving disco and violent gyrations of the cruising scene contrast strikingly with Allen's soft-toned flesh and delicate moaning orgasm. When Allen goes down on him, Pacino's passion rises as the throbbing Village theme invades his senses. The sequence arouses, perhaps in a trite or superficial way, a heterosexual's most basic fear of homosexuality: are the physical aspects of this act really any different when performed by a man instead of a woman?

Friedkin does not pause to answer his question, driving on through increasingly dramatic sequences, fading out and fading in until he leads us back to the disco on Christopher St. This time, Pacino does not refuse the guy who grabs his hand and pulls him to the dance floor. He moves furtively at first, apprehensive. Male bodies fill the cave, twisting, punching, kissing, biting, stroking, tearing. On the wall, a giant neon American flag blinks omnisciently. A man in an executioner's leather mask watches from the side. Pacino's partner spins and flicks his blond curls. The drum pounds louder, the montage quickens, the American flag flashes, glaring like a Puritan God, a caretaker of the Judaeo-Christian sex ethic, a last warning before--

SUDDENLY, PACINO WHIRLS in a frenzied freak-out, pumping his body and punching his hands into the air, a wild, abandoned look frozen in his tumescent eyes. "I don't think I can handle it," he whines later to Sorvino. "Things happen to me.. I'm not afraid...I can't deal with it." But Sorvino coaxes him back to the job, ironically affectionate to his protege, paternally hugging him and gesturing warmly.

As Cruising develops into a leather-coated cat-and-mouse story, Friedkin's strange perceptions of New York cops become clearer. They are crass morons as he presents them, maligning the cruisers and transvestites, raiding apartments at the wrong time, busting the wrong guys, torturing criminals and failing miserably to prevent the killings. Throughout the film, however, Friedkin casts them as good guys. They are the New York cops of 1977, paralyzed and pressured by a maniac who hears voices that tell him to kill.

Like Son of Sam, Friedkin's killer is an impotent homosexual. He's a Columbia student who forays nightly to Christopher St. with the words of his long-dead father ringing in his ears: "You know what you have to do..." So he kills; to please his father, to expiate his self-hatred, his homosexuality, to obey the Catholic commandments he reads religiously, he hunts on Christopher St. for sacrificial victims. After each stabbing he mutters to the ghost of his father, "You made me do it."

Pacino and the killer meet inevitably, a showdown in a green Garden of Evil under the bridges and tunnels and viaducts--the labyrin-the--of Morningside Heights, along the glistening, lamplit paths where Pacino cruises for the last time. They stare at each other, Pacino now affecting an effeminate walk. They throw down their burning fags in a mutual invitation to duel. Pacino steps out of his pants, urging on the killer ("get 'em down, I want to see the world") who whips out his blade. Pacino wounds him with his own knife and collapses against a wall, naked.

But Friedkin's unjustifiable massacre of sensibility reels on Ted, Pacino's neighbor, is murdered and while all clues point to Ted's jealous roommate as the culprit, Friedkin knows better. In an ambiguous series of elliptical shots, the director hints that Pacino has butchered Ted in a bizarre exorcism of his homosexual passion. Like the priests who die to save Regan in Friedkin's last sensationalist film, Ted dies to save Pacino's heterosexual soul.

It is a sick conclusion. Pacino emerges from the close, dark den on Christopher St. into the airy, white space of his girlfriend's apartment. Having finally shed his leather garb, he shaves, staring at his image in the ubiquitous mirror, confronting his self a last time, peeling away his homosexual mask. His ordeal has ended, the beast has been crushed, he is again normal.

Friedkin closets his film in ambiguity and elliptical action (he apparently cut several shocking scenes to appease viewers). Though it is superbly photographed in threatening shades of black, grey, blue and purple with effective use of moving and hand-held cameras, neither the characters nor the plot hold enough weight. Pacino has barely 100 lines. He is fine, as usual, but he is little more than Friedkin's pawn; the script never explores his relationships with Allen or Ted beyond a superficial level.

Cruising is unsatisfying as drama and disturbing as a sexual statement. Several brilliant moments of cinematic tension get lost in a rush of misguided, Puritan moralism. Pacino's shave in his final sequence connotes the removal of Cain's permanent scar or Hester Prynne's letter, as if homosexuality were a blight on American society that must be removed through violence. Friedkin claims Cruising "is not an indictment of the homosexual community," yet tacked-on words cannot temper his dangerously powerful images. There are real demons to exorcise--beyond Christopher St.