Crack cocaine user Houston, 48, was found dead under the bath water by her bodyguard in luxury suite number 434 at the Beverly Hilton Hotel on Saturday afternoon, which is said to have been littered with bottles of prescription pills.
On Thursday she is said to have gone on a 'wild binge' where she clashed with security guards. The next evening she 'partied heavily, drank and chatted loudly' with friends at the hotel bar.
Bottles of Lorazepam, Valium, Xanax and a sleeping medication were found in the hotel room, it has been claimed.
The drugs were believed to have acted as sedatives, causing her to fall asleep in the bathtub once they had been mixed with alcohol from the previous evenings.
Paramedics battled to revive the singer but she was pronounced dead at 3.55pm, hours before she had been due to perform at a pre-Grammys party at the same hotel.
Los Angeles coroner's office refused to comment on rumours that water was found on her lungs, indicating she had drowned.
It said further details will not be officially released until a police investigation is completed, which may take between one and two months, and revealed no one may visit the body while it is in their custody.
At first it was thought that singer and reality TV star Ray-J, her on/off boyfriend who at 17 years younger dated her between 2007 and 2009 and was believed to have rekindled the romance, found the star.
But the brother of pop star Brandy, who made a sex tape with Kim Kardashian in 2003, later released a statement saying he 'was nowhere near the scene but no less distraught'. He added that he had received 'missed calls' from his ex, and said: 'We all gotta live with that.'
Houston's ex-husband Bobby Brown, with whom she had a notoriously turbulent 14-year relationship riddled with drug use, was in Nashville at the time of her death and his daughter's trips to the hospital.
Brown - whom she blamed partly for her drug issues - was said to be 'in and out of crying fits' upon hearing the news - but still appeared on stage on Saturday with his band New Edition, and cried out 'I love you, Whitney!' in the middle of the concert.
Singer Johnny Gill, one of Brown's New Edition bandmates on tour in Memphis with the star, said: 'Bobby is struggling and he's devastated.'
