SHOCKER! WHITNEY HOUSTON didn’t have to die as she made a last desperate bid to reach out! PLUS: RAFFLES VAN EXEL speaks exclusively to The ENQUIRER about WHAT REALLY HAPPENED!

Someone close to Whitney spent 15 minutes sweeping her hotel suite of cocaine before calling for help, The ENQUIRER has learned exclusively, and that may have meant the difference between life or death for the pop icon.

Now members of Whitney’s family and her entourage are consumed with guilt over her tragic death and blaming each other for failing to save her, say insiders.

Whitney’s lifeless body was found in her bathtub at the Beverly Hilton hotel on Feb. 11, and her sister-in-law/manager Pat Houston has admitted that she ignored repeated phone calls from Whitney that day – and at least one of them was shortly be­fore her death.

“It was as if Whitney was making her own 911 call to Pat,” a family insid­er told The ENQUIRER.

“Pat has to feel guilty because Whitney needed her in her final hours, but Pat never answered her calls.”

Now a source with intimate knowledge of the “Bodyguard” star’s final hours has stepped forward to reveal a man delivered $1,000 worth of cocaine to her suite shortly before she died.

“Whitney either called or texted this man – a provider of her drugs – who she knew was nearby,” the source told The ENQUIRER.

“As she’d done many times before, she had a $1,000 bag of coke – known in street lingo as a ‘g pack’ – delivered to her suite.

“Then after scoring the coke, Whitney took her final drug hits in the privacy of her bathroom. Behind the closed bathroom door, and before entering the tub, she laid out some lines on a small makeup mirror and snorted them.”

Autopsy results show Whitney was still alive when bathwater flooded her lungs. While there are conflicting reports about who discovered her body, the source claims about 15 minutes elapsed before paramedics were called at 3:43 p.m. During that time, “someone cleaned up, re­moving the mirror and all traces of the cocaine,” the source said.

 When Beverly Hills Fire De­partment paramedics arrived, they performed CPR on Whitney, 48, before pronouncing her dead at 3:55 p.m.

As Whitney’s lifeless body lay nearby, a vicious argument erupted between Pat Houston and her brother Ray Watson, who was one of Whitney’s bodyguards, over the death of the star, the eyewitness said.

“Pat screamed at Ray, ‘How could you let THIS happen? I thought you had all the bases covered! You were watching her!’ ” the source recalled. “Ray was absolutely devastated. All he could do was hang his head as tears ran down his face.”

Now Pat, who’s married to Whitney’s older brother Gary, and Ray are blaming themselves for the diva’s tragic death, said the source. “They think that if they’d been present and suspected something was wrong, they could have hauled Whitney out of the tub and maybe resuscitated her,” said the source.

“Other members of the Houston family and Whitney’s entourage are also pointing fingers at each other, both publicly and behind the scenes, as to who’s really to blame for her death.”

 Thos present at the scene included Whitney’s brother Gary, her daughter Bobbi Kristina, her personal assistant Mary Jones and hairstylist Tiffanie Dixon.

Also present was a controversial member of Whitney’s entourage named Raffles van Exel. He has flatly denied Internet claims that he was one of Whitney’s drug dealers and removed illegal drugs from her hotel suite.

On the website “Diary of a Hollywood Street King,” celebrity blogger Jacky Jasper alleged van Exel told a reporter in his native Holland that “he was the ‘only’ person authorized to clean all the drugs and paraphernalia out of the room.”

The website also claimed van Exel was “re­vealed to be Whitney Houston’s drug dealer.”

“That’s ridiculous,” van Exel told The ENQUIRER. “I did get a call from a station (in Holland) a couple of days after Whitney died and spoke about her death in generalities. But of course I didn’t say THAT.”

However, he did admit to being in Whitney’s suite before authorities arrived.

“I came into Whitney’s room just before the police and paramedics did,” he said.

“I don’t know what drugs were there, but the place was clean when I arrived.

“Only after the police had gone and Whitney’s body had been removed did I help her brother Gary and his wife Pat pack up Whitney’s clothes and other possessions.

“That was the only so-called ‘clean-up’ I was involved in, and it had nothing to do with drugs.

“All three of us were in shock then. We were crying. We couldn’t believe that our beautiful Whitney was gone.”