Whitney Houston was "underwater and unconscious" when she was found in her Beverly Hilton hotel room.
Police have confirmed attempts were made for 30 minutes to save the singer after she was discovered by a member of her staff on Saturday afternoon.
Beverly Hills Police spokesman Lt Mark Rosen said in a press conference: "She was underwater and apparently unconscious. Ms Houston was pulled from the tub by members of her staff and hotel security was promptly notified."
Hotel security responded when called but were "unable to reviver her" after initiating CPR.
He added: "At approximately 3.55pm, Whitney Houston, age 48, was pronounced dead at the scene."
The coroner's office have been asked to keep their findings into how she died secret until they were complete.
The police statement concluded: "As can be expected in a high-profile incident such as this, there have been many rumours circulating and much speculation by the media and the public.
"In order to minimise such speculation, the Beverly Hills Police Department has asked the coroner's office to place a security hold on their findings until they have a complete and final report prepared."
Daughter finally able to see body
Bobbi Kristina Brown will see her mother Whitney Houstons body for the first time today.
The 18-year-old is one of a limited number of people who will attend a private viewing of the singers body at the Whigham Funeral Home in Newark, New Jersey.
According to TMZ.com close members of the family where keen to have a special moment at the home without cameras before the funeral at the New Hope Baptist Church on Saturday.
Bobbi Kristina - the daughter of Whitney and her ex-husband Bobby Brown - was stopped from seeing her mother after she died at the Beverly Hilton Hotel last Saturday.
Despite shouting at police officers she was still denied access.
The next day, Bobbi Kristina was taken to Cedars-Sinai Hospital in Los Angeles on a stretcher after suffering an anxiety attack.
However she was released on Monday and her father said she was learning how to deal with the departure of her mother.
He said in a statement: We continue to provide love and support to Bobbi Kristina. She is dealing with the tragedy of her mother's death and would prefer to do it outside of the public eye. I ask again that our privacy be respected."
Godmother sings Whitney's praises
Whitney Houston had the heart of a champion - according to her godmother Aretha Franklin.
The 69-year-old singer has paid tribute to her goddaughter, claiming that while she was knowledgeable about the challenges the hitmaker - who died aged 48 - had, she was still impressed with how she dealt when critics mauled her voice during her last tour.
She said: We were all aware of her challenges. And I was always rooting for her.
Looking back now, I recall her European tour. Still exciting, but unable to sing what she wanted to had been disheartening. And yet she stood night after night and endured unappreciative audiences with the heart of a champion.
Aretha - who herself has battled personal problems in her life, most recently her weight - has seen previews for Whitneys movie Sparkle, which will be released later this year, and admits she was delighted with how it looked.
She told People Magazine: Seeing previews for the new Sparkle
movie I thought, boy, she looks good. Healthy, fresh and has that
twinkle in her eye.
