LOS ANGELES » It was a dank, rain-sodden Raymond Chandler kind of morning, as if some omnipotent auteur rang the studio and ordered a classic film noir sky. Cumulonimbus clouds the color of a snub-nosed revolver hovered with ominous intent, and tires on slickened freeway lanes gave off a sinister, knife-sharpening hiss.

Only a sap would be out on a day like this, searching for the seedy, serrated soul of L.A. noir.

Yet tourists often come here, searching for the Los Angeles of the 1930s, ’40s and ’50s. They seek remnants of a period when the city was an incubator of tawdriness, a place where corruption, double-dealing and unchecked passion gave rise to a literary and cinematic genre that to this day captures the imagination.

Fitting, then, that the weather would cooperate and set the mood. But, really, the sun has never served as a nourishing, warming presence in L.A. noir; rather, it’s a carcinogenic inferno bent on mocking desperate dreamers with incessant, incongruous cheeriness.

Already this morning, fueled by too many black and bitter cups o’ joe, you’ve swung by the Southern Pacific Railroad Depot in Glendale. Scene of the crime in the seminal noir thriller "Double Indemnity," you picture a hunch-shouldered, stubble-jawed Fred McMurray skulking around the tanned Mission Revival structure, not stopping to admire the twisted columns or handcrafted ironwork.

Now you head downtown and to the Hotel Barclay (formerly the Hotel Van Nuys), one of Chandler’s haunts and the setting for the gruesome ice pick-in-the-neck murder scene in his novel "The Little Sister." All that remains is the art deco sign; the hotel has long been shuttered, its windows cracked and duct-taped.

Move along, bub. Nothing to see here.

Plenty to see at the nearby Millennium Biltmore, the famous, swanky downtown hotel that once hosted the Oscars and retains its ornate, retro opulence. This was, legend has it, the last place the Black Dahlia (aka Elizabeth Short) was seen in 1947 before her dismembered body was discovered in a weedy patch south of town.

That’s a real-life murder, pal, not some made-up movie plot. (Although, this being Los Angeles, where fact and fiction can quickly meld, it eventually became a feature film.) In its day, the Black Dahlia case — still unsolved — created a media frenzy: Think O.J. Simpson trial to the nth degree.

In the expansive lobby, featuring a stained-glass ceiling and marble fountains with water trickling out of lions’ mouths, you try to picture the Black Dahlia in her low-cut black dress, snapping gum and batting heavily mascaraed eyelashes as she slinks out the door toward her fate.

You approach a dame behind a desk. She has an alluring smile, one that can make even the most cynical thug ask impertinent questions. She says her name is Nicole Solum. Claims she’s the hotel concierge. You have no reason to doubt her.

"We get people bringing it up all the time," she says. "Sometimes we get tour groups. Sometimes they’ll ask if (the Black Dahlia’s) ghost haunts the halls."

What of it? Is it true about ghosts? Spill it, sister.

"Well, this is an old hotel …" she says, leaving the answer dangling. "We don’t mind people asking. We even have a cocktail in the bar called the Black Dahlia."

But there’s no time to imbibe the novelty martini. A teeming metropolis awaits.

You hightail it to Hollywood Boulevard and Musso & Frank Grill, where in a back room celebrated writers of the era (everyone from Chandler to Nathaniel West to F. Scott Fitzgerald and William Faulkner) used to convene to rinse away brain cells after selling out and penning noir scripts.

Upon arrival you see the landmark eatery is smack-dab in the middle of the area’s cheesiest tourist trap, an area best avoided unless you want to beat yourself up with existential ennui.

Make a sharp right on Ivar Street and search for West’s rented cottage, the place where he wrote "The Day of the Locust." In the novel he calls Ivar Street "Lysol Alley" and says the rooming house was "mainly inhabited by hustlers, their managers, trainers and advance agents." Now it appears little more than a clean, middle-class neighborhood of apartment buildings and bungalows. Beyond the gentrified facade? Well, who knows?

Hollywood Boulevard can quickly wear on even the most resolute cultural gumshoe, so you travel west on Santa Mon­ica Boulevard to the blood-red exterior of the Formosa Cafe, away from the tourist hordes. Back in the day, this watering hole was said to be a police-protected hangout for gangsters, molls, prizefighters and bookies.

Moviegoers might remember the Formosa as the setting in the neo-noir 1997 flick "L.A. Confidential" where a detective played by Guy Pierce says to a bleached blonde in a booth that "a hooker cut to look like Lana Turner is still a hooker; she just looks like Lana Turner," while worldly partner Kevin Spacey smirks because he knows it really is Lana Turner sitting there.

L.A. IS SO movie-saturated that you forget the crimes were real. A trip northeast of town to the Los Angeles Police Historical Society Museum — housed in a decommissioned police precinct headquarters — slaps some sense into you. It also makes you realize that the city’s noirishness both predates the film genre and mutated into a surrealist noir in the ’60s and beyond.

A museum dedicated to the LAPD might at first come off as a mug’s game for noir fans, given that the Rodney King and Rampart corruption scandals are not mentioned. Yet the museum provides plenty of grisly exhibits about cases that defined the city, from the Black Dahlia to the Manson Family and beyond.

Remember the 1973 Symbionese Liberation Army shootout in South L.A.? It is memorialized pictorially and on video. Evidence includes gas masks and pipe bombs retrieved from the SLA safe house, and a red-and-black serpent flag like the one Patty Hearst posed in front of in her "Tanya" transformation.

Remember the 1997 North Hollywood bank robbery shootout and daylong hostage situation played out on live TV? The museum shows mannequins dressed in the bloodstained body armor of the robbers and chillingly displays the bulletproof bank teller’s window with gunshot indentations intact.

But it’s the traditional period pieces that best recall the noir era. Jail cells remain from the 1940s. Batons and blackjacks merit their own display case, as do gangster-period machine guns. Lurid headlines, often flanked by fingerprints and mug shots, from the period’s infamous kidnappings and murders line the walls. In an only-in-L.A. twist, fiction mingles with fact with tributes to Jack Webb ("Dragnet" fame) and the TV show "Adam-12."

As you wander the drafty floors of the old police station, the museum seems to tell you that the good guys (the cops) always won in the end. It’s a sunny and sanitized display, right down to the life-size cutout of former Police Chief Daryl Gates, toothy grin and all, at the front desk.

Your noir brain, however, recalls that line in Orson Welles’ "Touch of Evil," filmed in nearby Venice: "A policeman’s job is easy in a police state."

Seeking answers, you buttonhole the flatfoot in charge, museum director Glynn B. Martin, a retired cop, whose enthusiastic handshake crunches your metacarpals.

"These are all materials given to us through court processes or the DA or the Police Department," he says in just-the-facts-ma’am tone. "We go through the formal disposition process. We’re a stand-alone nonprofit but obviously work in close cooperation with the department.

"For the Black Dahlia (exhibit), robbery-homicide has an entire file cabinet with tens of thousands of pages of materials and photographs, so we were able to draw from that. But nothing gruesome. We’re not a ghoul show."

SANITIZE IT if you must, but noir can be gruesome.

Chandler, from "The Long Goodbye": "Out there in the night of a thousand crimes, people were dying, being maimed, cut by flying glass, crushed against steering wheels or under heavy tires. People were beaten, robbed, strangled, raped and murdered."

Where to see the lurid underbelly? Tipsters point you to the Museum of Death on Hollywood Boulevard. There, beyond the serial killer and suicide cult memorabilia and the room dedicated to the embalming process, lies the California Death Room.

Not for the squeamish, it shows graphic photos of actress Sharon Tate, murdered by the Manson Family; even more hideous severed-torso police shots from the Black Dahlia investigation; and a wall dedicated to later serial killer cases — the Hillside Strangler and the Night Stalker.

You approach two young women who don’t look to be the type to frequent a joint like this, but here they are. They say they’re tourists from Memphis, Tenn. They look honest, wholesome, not yet beaten down by the naked city. You take them at their word. You ask why they’ve come here.

"This kind of thing always intrigues me, you know," says Hannah McCaleb. "Like, we don’t know what death is, so we want to come and find out as much as we can."

The femme fatale who runs the Museum of Death, a redhead named Kathy Schultz, says she has gotten death threats from people who say "we should not be promoting serial killers, these despicable people."

She adjusts her horn-rim glasses and casts a gimlet eye on you: "Look, I love life and all aspects of life. And part of life is death."

You leave and can’t get that William Holden line from "Sunset Boulevard" out of your head: "Funny how gentle people get with you once you’re dead."

Dusk approaching, the sky becomes, in West’s words, "one of those blue and lavender nights when the luminous color seems to have been blown over the scene with an airbrush."

You have one last stop. You drive south on the freeway 20 miles to Rancho Palos Verdes and Green Hills Memorial Park. You’re looking for Charles Bukowski’s grave. It’s been said that Bukowski’s gritty, dissolute poetry and prose brought L.A. noir into modern times.

Certainly, he had the seediness part down. At least two dozen bars in L.A. boast that "Bukowski drank here" before his death in 1994. You’re told that Bukowski fans, in tribute, often drink, smoke and fornicate upon his grave.

All you see at plot 875 are two wilted flowers in a cup, rain-soaked and missing a few petals.

His epitaph reads, "Don’t try."

A perfect noir image.