Whitney Houston was found in a hotel bathtub but it'll take weeks to determine precisely how she died, a Los Angeles coroner's official says.

Assistant chief coroner Ed Winter told reporters Sunday afternoon that police had requested that no details about Houston's autopsy be publicly released. He said toxicology results would take weeks and the results were needed to determine how the singing superstar died in a room at the Beverly Hilton Hotel on Saturday afternoon.

Winter declined to release any details about what investigators found in the room, but said coroner's officials were not ruling out any potential causes of death. He said there were no signs of trauma on Houston's body.

Houston was found by a member of her entourage. Paramedics worked in vain to revive her, and she was pronounced dead shortly before 4 p.m.

Earlier Sunday, Houston's family issued a statement calling her death both "devastating" and an "unimaginable tragedy," as fans rushed to buy her albums and download her hit singles: "This is a unimaginable tragedy and we will miss her terribly. We appreciate the outpouring of love and support from her fans and friends."

Houston's greatest hits — including I Will Always Love You, I Wanna Dance With Somebody, How Will I Know, Saving All My Love For You and Greatest Love of All — are at the top of the iTunes charts and her Greatest Hits album is No. 1 on Amazon.com

On Sunday, the Beverly Hills Fire Department said Houston's daughter, Bobbi Kristina Brown, 18, was taken from the Beverly Hills Hilton around 10:30 a.m. local time, less than a day after her mother died in a room at the same hotel. She was released mid-afternoon after being treated with what a family member called stress and anxiety.

'Unbelievable'

Houston's death Saturday afternoon in a hotel room came hours before she was scheduled to appear at an annual pre-Grammy party that introduced her to the industry decades ago and was expected to honour the six-time Grammy winner. Sunday's gala was altered to include a tribute to Houston, with a performance by Jennifer Hudson and Chaka Khan. Houston was once a backup singer for Khan.

Aretha Franklin, her godmother, said she was stunned.

"I just can't talk about it now," Franklin said in a short statement on Sunday. "It's so stunning and unbelievable. I couldn't believe what I was reading coming across the TV screen."

Houston's ex-husband, and Bobbi Kristina's father, Bobby Brown performed in Mississippi Saturday night.

"First of all, I want to tell you that I love you all,” an emotional Brown said at the concert where he had reunited with his old group New Edition at a locale near Memphis, Tenn. “Second, I would like to say, ‘I love you, Whitney.’ The hardest thing for me to do is to come on this stage.”

Sean Cheesman, a renown dancer and choreographer who originally hails from Calgary, recalled Houston as being "a real good comedian."

Cheesman appeared with Houston in the 1992 film The Bodyguard and choreographed Houston in the movie, and in the music video for her song I'm Every Woman.

Police responded to an emergency call at the Beverly Hilton hotel in Los Angeles at about 3:45 p.m. PT Saturday, said Lt. Mark Rosen with the Beverly Hills police. Paramedics who were already at the hotel because of a Grammy party rushed to Houston's fourth-floor suite and attempted to revive her but they were unsuccessful, Rosen told KABC-TV.

No obvious signs of 'criminal intent'

Houston was pronounced dead just before 4 p.m., Rosen said. "There were no obvious signs of any criminal intent," Rosen said.

Her death sparked shock and reaction from other singers and celebrities.

"Heartbroken and in tears over the shocking death of my friend, the incomparable Ms. Whitney Houston. She will never be forgotten as one of the greatest voices to ever grace the earth," posted Mariah Carey on Twitter.

"Whitney Houston was the greatest singer I've ever heard and she will be truly missed," said Tony Bennett, also onTwitter.

Just days before her death, the pop singer had been making the rounds before the Grammy event, appearing at rehearsals and offering advice to singers Monica and Brandy. On Thursday, she appeared with fellow singer Kelly Price on stage at a Hollywood club, where she sang the hymn Yes, Jesus Loves Me to loud cheers.

With Houston's daughter Bobbi in the audience, the women shared a long hug and talked about their lives and families throughout the night, Price recalled Saturday. Houston spent hours standing on the side of the stage at the event honouring R&B music then joined partygoers on the dance floor, she said. "Whitney on Thursday night was one of the girls."

"She was happy," Price said. "She was the Whitney I always knew."

Soul singer Kenny Lattimore, who co-hosted the R&B event, said Houston seemed to be having a good time, making her sudden death "such a shock for me." He said Houston didn't appear to be having any issues.

Singer struggled with drug addiction

Houston struggled for years with addiction to cocaine, marijuana and pills and the years of hard-living took a toll on her once-pristine voice. During rehearsal for a pre-Grammy event Thursday, Houston appeared disheveled, sweated profusely and her breath smelled of liquor and cigarettes, said a source who was present but not authorized to speak publicly.

Despite more than a decade of problems, including her divorce from Brown and numerous instances of erratic behavior, Houston was working toward a potential comeback. She had just completed work on a remake of the film Sparkle, a project she'd worked to develop for years.

Yet some speculated that she was under the influence after the Thursday club appearance, when paparazzi snapped photos of Houston leaving and looking dishevelled. Price called the rumours "totally untrue."

There was a family feel to the gathering, she said: "Our kids were there."

Price said she and Houston were planning another reunion, and that she was set to appear at the pre-Grammy gala thrown by her longtime mentor, Clive Davis, on Saturday night. Davis had expected that Houston would sing at the party, which went on as planned, he explained, because the diva would have wanted it that way. It took place in another part of the hotel from where her body was being examined by coroner's officials.

"I am personally devastated by the loss of someone who has meant so much to me," Davis said. "She was full of life, looking forward for tonight. She loved music and she loved this night that celebrated music."

Jennifer Hudson to perform Grammy tribute

Officials have released few details about how Houston was found or what killed her. A member of her entourage found the singer and alerted hotel security and paramedics already on site for Davis' gala. They failed to revive the singer.

In the hours after Houston's death, fans chose to remember the singer in better times, when her soaring voice introduced a new generation to the Dolly Parton song I Will Always Love You and propelled the film The Bodyguard into blockbuster status.

Her songs and albums quickly became top-sellers on iTunes, and fans and celebrities alike shared remembrances and accounts of impromptu memorials on the social networking site Twitter. Her death on the eve of the Grammy awards has already prompted changes to the broadcast Sunday, with Jennifer Hudson and Chaka Khan scheduled to perform a tribute during the show.

Price said her friend would want to be remembered as God-fearing and a good mother, rather than simply a singer. She said she and Houston often discussed parenting and issues unrelated to their musical careers.

She recalled her last night with Houston, the words they shared before Houston delivered what would be her final performance.

"I never ever imagined I'd be talking about her because she's not here," Price said.