Did somebody tamper with the evidence in Whitney Houston's hotel room on the night she died?
That's the explosive speculation now being made because cops say no cocaine was found in Houston's suite at the Beverly Hilton Hotel, even though the coroner's report says she had "an acute dose" of cocaine right before "accidentally drowning" in the bathtub.
Beverly Hills police say their investigation into Houston's death is not closed, but they're not commenting on whether they're looking into possible evidence tampering.
Besides no cocaine or drug paraphernalia being found in Houston's hotel room, one report says her bedsheets were also missing.
There are now growing calls to find out what happened in the minutes before cops arrived.
Dr. Charles Sophy said, "Absolutely, we should find out where that cocaine went, where it came from, and I think we also need to understand where did she get all these other prescription drugs."
Bobby Brown's sister, Leolah, appeared on HLN with addiction expert Dr. Drew Pinsky and ripped into Houston's boyfriend, Ray J, accusing him of being Houston's "runner boy."
Leolah Brown said, "I saw Ray J coming out of the hotel hiding his head, being pushed into the car. Why? I looked and I said, why is he hiding? Why is he hiding his face?"
In a statement, Ray J's rep lashed back, and denied her claims, and said Leolah Brown "falsely claimed that Ray J was at the hotel and contributed to Whitney Houston's death."
And Ray J's family is also fighting back. His sister, Brandy tweeted: "When you point your finger at someone, there is always three fingers pointing back at you...Including the middle!"
His mother, Sonja tweeted: "I'm very well aware of the false accusations and trust me, I'm wide awake. I am nowhere close to being asleep on this matter."
We're learning more about the Los Angeles County Coroner's report that says: "Whitney Elizabeth Houston died from accidental drowning, with cocaine use a contributing factor."
Craig Harvey, Chief of Operations at the Los Angeles Coroner's office said, "It appeared that the cocaine had been used in the time period just probably immediately prior to her collapse in the bathroom at the hotel."
The report also revealed the 48-year-old Houston sufferred from atherosclerotic heart disease.
"We feel that the cocaine, coupled with the atherosclerotic heart disease, complicated her condition. Chances are, had she not had the pre-existing disease and cocaine use, she might not have drowned," said the Coroner.
Former medical examiner and pathologist Dr. Bill Manion told INSIDE EDITION's Diane McInerney how he believes Houston died.
"I believe she took the cocaine maybe 15-20 minues before she got into the bath," said Dr. Manion.
The arteries in Houston's heart were already enlarged from years of drug abuse. The arteries began to constrict because of the effects of the cocaine.
Dr. Manion believes she suffered a heart attack, passed out in the bathtub, and was helpless as water filled her lungs and she drowned.
McInerney asked Dr. Manion, "What really killed Whitney Houston?"
"Ultimately, it's the drugs. It's the cocaine. If the drugs hadn't have been there, she wouldn't have passed out. If the cocaine hadn't been there, there's no reason for her to pass out in that water and then slip under the water and suffocate," said Dr. Manion.
There were several drugs other than cocaine in her system including marijuana and Xanax, and the muscle relaxer Flexeril, and the allergy medication Benadryl, but they did not contribute to her death, the coroner's report says.
"We know that when she slipped under the water she was still alive," said the Coroner.
The report states that there is "no indication of foul play" in Houston's death.
Her grieving mother, Cissy Houston is reportedly "shocked" to learn Whitney was using cocaine at time of her death.
Houston's sister-in-law and manager, Patricia Houston said in a statement: "We are saddened to learn of the toxicology results, although we are glad to now have closure."