What killed Whitney Houston?

Those who loved the troubled diva are obsessed with finding the answer to an altogether different mystery — who is responsible for her tragic and untimely demise?

Beautiful Whitney died ugly in a tub full of water in an anonymous LA hotel suite the night before the music industry’s Super Bowl, the Grammy Awards. As her life ebbed, a slim door was all that separated the dying singer from handlers and paid toadies — enablers who pass as family for lonely celebs who can’t, or won’t, care for themselves.

But one thing should be as clear as Whitney’s once-crystal voice: At 48, with decades before her, Whitney Houston killed herself.

She did this as surely as Kurt Cobain armed with a shotgun. As Heath Ledger juggling bottles of prescription pills. Michael Jackson with a toxic syringe. Her demise came as suddenly, and predictably, as Amy Winehouse with a gallon of booze. Billie Holiday wasn’t the first. Poor Whitney won’t be the last.

But as certainly as Whitney hastened her own passing, another picture emerges: There was no one to stop her. She had plenty of help.

Is the music industry complicit in her death?

As authorities await toxicology reports, Chaka Khan became the only renowned performer who dared to criticize Whitney’s peers for sullying her memory.

Khan grew palpably furious that Whitney’s “mentor,” music impresario Clive Davis (pictured), carried on with his pre-Grammy party Saturday night at the Beverly Hilton, hours after Whitney’s lifeless body was found in a bathroom upstairs.

Whitney was still in the bathtub as guests partied on, willfully oblivious to the horror. This led revelers in ball gowns and tuxes to bump into crime-scene detectives in elevators, like something out of a slasher flick.

“I thought that was complete insanity,” a visibly upset Khan told CNN.

Davis told party-goers that he kept the show alive for Whitney’s sake. “Simply put, she would have wanted the music to go on,” he said. Khan was disgusted.

“Knowing Whitney, I don’t believe she would’ve said, ‘The show must go on.’ ” said Khan. “She’s the kind of woman who would’ve said, ‘Stop everything. I’m not going to be there.’ ”

Khan ducked out of singing at a Whitney tribute at the Grammys with Jennifer Hudson, who has turned into the go-to girl in times of crisis, also performing at the obscene Michael Jackson memorial in Los Angeles.

So who is to blame?

Whitney’s seething relatives blame ex-husband Bobby Brown. Some want to ban the singer, with whom Whitney began her downhill slide, from her funeral this weekend. Authorities are also taking a look at Whitney’s doctors who prescribed powerful sedatives. She was spotted twice the week before she died visiting various physicians’ offices.

I still wonder — could Whitney be saved?

It makes me angry that a woman — the mother of Bobbi Kristina, who, before she turns 18 next month, filled the unhealthy role of her mother’s caretaker — killed herself while the world watched. But said NYU music technology professor J. Chris Griffin, a producer who’s worked with Madonna and Kelly Clarkson, damaged people are drawn to music.

“In the music business, you get a lot of adoration from fans, as long as you’re doing well,” he said.

“Inevitably, things don’t go great, and the addictions start. We’re always trying to recreate that high, the audiences on their feet. Her story is not unique in the music industry.”

NYU psychology professor Mary McRae says it’s imperative that addicts “get away from people, places and things” that cause relapses. Days before she died, a disheveled Whitney was spotted drinking and partying.

Maybe she felt she had no one to lean on besides folks who don’t have her best interests at heart. Or maybe she just didn’t care to change.

There will be blame. Dr. Conrad Murray was convicted of involuntary manslaughter for helping Michael Jackson commit suicide by propofol. Whitney, too, found the combination of friends and associates who helped her end her life.

There is no one else to blame.

She’s Oprah ‘Lose’-frey

Newly pathetic Oprah Winfrey issued a nervy tweet during Sunday night’s Grammys. O begged her 9 million followers to change the channel to Oprah’s flailing OWN network — “especially if u have Neilsen [sic] box.”

Well, Nielsen forbids TV folks from asking people with ratings-counting boxes in their homes to watch particular shows. The company may punish viewer-challenged OWN where it hurts. “We may withhold, breakout and/or make a note in the ratings,” said Nielsen.

Cheating is not an option. Even for Oprah.

‘Fed’ up with MTA

Gross. Garbage-eating rats are taking over the subways. But the new MTA chairman, “Rat Czar’’ Joe Lhota — who earned his nickname slaying rats as Rudy Giuliani’s deputy mayor — won’t back a proposed law to ban eating underground. In a fit of misguided paternalism, Lhota said he’s seen poor kids get their only meal, breakfast, on the train to school. He forgets that the kids he pities get free breakfast and lunch as well.

Pretty soon, kids will be fighting rats for crumbs. Ride the trains a little more, Joe.

Lin-ger on sofa a while

New York Knicks phenom Jeremy Lin has a Harvard degree. He crushed Kobe Bryant’s LA Lakers by sinking 38 points at Madison Square Garden last week, while pushing TV ratings into the stratosphere (without Time Warner). Plus, Linsanity helped boost the price of MSG stock to a 52-week high.

So what have you done with your day?

The 23-year-old hoops star, who six weeks ago seemed destined for Mensa rather than the NBA, had been crashing on a couch in his brother Josh’s Lower East Side one-bedroom. A top decorator wanted to plant the sleeping giant on a $16,000 sleeper sofa, while Old Homestead offered the ill-fed bachelor free steaks.

But now, Lin has agreed to sublet a luxury apartment — in White Plains! Hot diggity. What will Lin do for fun? Curl up on multiple settees while puttering in his cavernous country kitchen?

Come back to the couch, Jeremy. You’re good luck for this town.

Bureaucratic inch worms

City government has gone mental.

A Chinatown newsstand that’s stood on the same spot for 35 years — since Jimmy Carter was in the White House and we all boogied down to “Saturday Night Fever’’ — is being evicted. City transportation officials suddenly discovered that the stand, where Marilyn Louie sells lottery tickets and newspapers seven days a week, is too close to a facing building. By a 3 whole inches! Louie must clear out by Feb. 29.

I suppose that Louie, who’s never held another job, will be tossed onto the public dole, while the city cries poverty. Way to go, fat bureaucrats.

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