Investigators have been working to piece together what killed Whitney Houston as the music industry's biggest names gathered for a Grammy Awards show that at times felt as much like a memorial as a celebration.

Coroner's officials said they would not release any information about a post-mortem examination carried out at the request of police detectives investigating the singer's death.

The singer was found in the bathtub of her room at the Beverly Hilton Hotel, but Assistant Chief Coroner Ed Winter declined to say anything more about the room's condition or any evidence investigators recovered.

He said there were no obvious signs of trauma on Houston's body, but officials were not ruling out any causes of death until they have toxicology results, which will take weeks to obtain.

Beverly Hills Police Lieutenant Mark Rosen said his agency may release more details about Houston's death later, but it would depend on whether detectives felt comfortable releasing any information.

A member of Houston's entourage found the 48-year-old singer unresponsive in her hotel room at the Beverly Hilton Hotel on Saturday, just hours before she was supposed to appear at a pre-Grammy gala.

Lt Rosen said there were no indications of foul play when Houston was found. Paramedics worked to revive her, but were unsuccessful and she was pronounced dead shortly before 4pm. He said he could not comment on the condition of Houston's room or where she had been found.

Meanwhile, Houston's daughter was taken to a Los Angeles hospital by ambulance on Sunday morning and later released. A source close to the family said Bobbi Kristina Brown was treated for stress and anxiety.

The 18-year-old, who is Houston's daughter from her tumultuous marriage to singer Bobby Brown, had accompanied her mother to several pre-Grammy Awards events last week.

"At this time, we ask for privacy, especially for my daughter, Bobbi Kristina," Bobby Brown wrote in a statement released about an hour after she was transported from the hotel. "I appreciate all of the condolences that have been directed towards my family and I at this most difficult time."