However, police have requested details of Whitney Houston’s autopsy not be released until a toxicology report can confirm how the singer died.
Assistant Chief Coroner Ed Winter, declined to release any details about what investigators found in the room. But he confirmed there were no signs of trauma on Houston’s body.
Houston, 48, was found dead in her room at the Beverly Hilton Hotel in Los Angeles hours before she was due to attend a star-studded party downstairs, on the eve of the Grammy Awards.
Detectives are pursuing the theory Houston accidentally drowned in the bath after taking prescription drugs and drinking heavily over the previous two evenings.
Houston, who has a daughter to ex-husband, singer Bobby Brown, had battled years of addiction to drugs. She was known to take anti-anxiety drugs, Xanax, valium and lorazepam.
Two bodyguards, a hairdresser and stylist were believed to have been in the singer’s room at the time of her death, and discovered her body, with her head under the water, after becoming concerned that she had been in the bathroom for more than an hour.
Paramedics tried to resuscitate Houston for 20 minutes but she was pronounced dead at 3.55pm (11.55pm GMT) on Saturday.
The singer’s 19-year-old daughter Bobbi Kristina was at the hotel at the time.
On Thursday, two days before Houston’s death, witnesses said she had displayed erratic behaviour, including doing handstands by the Beverly Hilton Hotel pool, and wandering aimlessly around the lobby. Later that night she was seen looking dishevelled at a Hollywood nightclub. A Video also showed her performing there briefly in a faltering voice.
Tributes have poured in since Houston’s death.
The Grammy Awards schedule was quickly altered to include tributes, including one to be sung by Jennifer Hudson.
Houston’s godmother, the soul singer Aretha Franklin, said: “I just can’t talk about it now, It’s so stunning and unbelievable. I couldn’t believe what I was reading coming across the TV screen.”
Mariah Carey said she was “heartbroken and in tears over the shocking death of my friend,” and Dolly Parton said: “Mine is only one of millions of hearts broken.”
Gospel-trained Houston was one of the world’s bestselling recording artists, with Songs like “I Will Always Love You” and “Saving All My Love” becoming global hits.
She released seven studio albums and sold 170 million CDs, singles and videos.
But her career began to unravel as she battled drug addiction and embarked on a tumultuous 15-year marriage to “bad boy” singer Bobby Brown.
She confessed to abusing cocaine, cannabis and pills, but famously denied using crack cocaine, saying: “I make too much money to ever smoke crack. Crack is wack.”
Houston’s once pristine voice became raspy and hoarse, she was unable to hit the high notes of her prime, and record sales nosedived.
She divorced Brown in 2007 and attempted a comeback, but her stage performances left many fans unimpressed. Some walked out.