Gleaming white tiles; pounding jets of water; a naked woman; a shadowy figure on the other side of the plastic curtain; is there anyone out there who doesn't know what happens next?

If not the most famous scene in the history of the cinema, the shower sequence in "Psycho," Alfred Hitchcock's black-and-white masterwork of 1960, is certainly the most imitated and parodied.

Though Norman Bates dispatches with the hapless Marion Crane in less than a minute, shooting the scene took seven days, 78 camera setups, the eleventh-hour addition of Bernard Herrmann's shrieking score for strings, several yards of flesh-colored moleskin, an actress, a stand-in and a body double -- the last of which is the putative subject of Robert Graysmith's ultimately baffling "The Girl in Alfred Hitchcock's Shower."

I say "putative" because the actual subject of the book is Graysmith's decades-long obsession with Marli Renfro, the red-headed nude model and dancer hired by Hitchcock in large part because her figure approximated Janet Leigh's spectacular curves.

In September of 1960, when Graysmith was still a college student, he discovered Renfro on the cover of Playboy and taped her image up on his wall: "I woke each morning to that cover -- its warm tones, haunting face. . . . Who was this redhead? She had an indefinable quality that made her unique, unforgettable." A die-hard Hitchcock fan, he had yet to learn of Renfro's role in the legendary "Psycho" shoot, but once rumors to that effect started circulating, the besotted young man vowed that he would one day write a book about the beautiful pin-up.

Graysmith indeed grew up to become a writer -- not a biographer, much less a memoirist, but rather the author of true-crime tomes including "Zodiac," about the still-unsolved San Francisco area serial killings of the late '60s and early '70s, and "Auto-Focus: The Murder of Bob Crane." But here's the catch: Renfro was no Bob Crane, who famously descended into a perverse netherworld of voyeurism and sex addiction before he was murdered.

Renfro was a free spirit who made a lifelong commitment to nudism, worked as one of Hugh Hefner's first bunnies and had a bit part in the nudie-cutie classic "Tonight for Sure," directed by up-and-comer Francis Ford Coppola -- all of which may have been titillating for the young author-to-be but hardly add up to the juicy stuff of true crime.

This may well be the reason Graysmith retreats here to a subject with which he feels more comfortable -- the sordid story of a little-known Los-Angeles-based serial killer named Henry "Sonny" Busch Jr., a momma's boy in the mold of Norman Bates who killed one of his many victims hours after watching "Psycho."

Graysmith bounces back and forth, chapter by chapter, between the psycho killer and the centerfold, interlacing gore and cheesecake.

This book is dedicated to James Ellroy, whose "My Dark Places," with its deft interlacing of personal memoir, true crime and police procedural (think Dostoevski on speed), was an obvious source of inspiration.

But Graysmith is no Ellroy. Parallel tracks, especially in genre books, are meant to converge, and we spend too much time waiting for the inevitable meeting of monster and maiden.

Even though the author begins the book with a series of pull quotes from Associated Press and other sources informing us that the young woman who met her fate in Hitchcock's shower was herself raped and murdered in 1988, the truest thing that can be said about this particular crime is that it was a case of mistaken identity -- the murdered woman, thought by some early reports to be Renfro, turned out to be someone else. Graysmith attempts to fill the vacuum at the center of his book with a coda constructed to mimic the plot of the film noir classic "Laura."

There is still fun to be had here, as the book is full of period color about the entertainment industry, the West's seedy underbelly and the burgeoning sexual revolution: nudist colonies in Topanga Canyon, the history of Vegas showgirls, Leigh's marital disharmony, Hefner's role in shattering sexual and racial taboos.

When all else fails, there is anatomical detail about Renfro's nipples, which "stood erect from unusually firm breasts." Perhaps we are supplied with this information as proof that the errant nipple some have claimed to glimpse in the shower scene is Renfro's. More likely it's just more filler. Sometimes, a nipple is just a nipple.

Kandel is the Edgar- and Agatha-nominated author of "Dial H for Hitchcock," the fifth book in the Cece Caruso mystery series.