Whitney Houston was "underwater and unconscious" when she was found in her Beverly Hilton hotel room.
Police have confirmed that attempts were made for 30 minutes to save the "Greatest Love of All" singer after she was discovered by a member of her staff on Saturday afternoon (February 11).
But by 3:55 p.m., Whitney Houston was pronounced dead.
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 revive her" after initiating CPR.
He added: "At approximately 3.55 p.m., Whitney Houston, age 48, was pronounced dead at the scene."
The spokesperson added that the coroner's office had been asked to keep its findings into how she died a 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 rumors circulating and much speculation by the media and the public.
"In order to minimize 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."