Singer Found in Hotel Bathtub Authorities today are investigating what caused the death of legendary singer Whitney Houston who captivated audiences with her powerful voice while battling drug use and a rocky marriage with Bobby Brown. On Saturday, paramedics raced to the iconic Beverly Hilton Hotel and found a lifeless Houston inside her hotel room bathtub, authorities said. Members of Houston's entourage reportedly found her unresponsive body and called hotel security. Officials tried to resuscitate the 48-year-old singer with CPR but were unable to revive her. Beverly Hills police Lt. Mark Rosen said she was pronounced dead at 3:55 p.m. "No obvious signs of foul play and no obvious signs of a cause of death," Rosen said. Los Angeles Coroner Office officials left with Houston's body around 1:50 a.m. An autopsy is expected to be conducted today or Monday, according to ABC News Los Angeles station KABC. The singer's cause of death remains unknown according to her publicist, Kristen Foster. The coroner's office declined to speculate how Houston died when asked about reports that she may have drowned. When asked about drugs in the room, Ed Winter, with the Los Angeles County Coroner's office, said he could not comment on it. Winter said he could not comment on the condition of the body and whether she was naked or not. Just hours before her death, Houston's mother, Cissy Houston, and her cousin, Dionne Warwick, reportedly both spoke to the singer and said there was no indication that anything was wrong. Warwick spoke to her over the phone to check that they were seated at the same table at Davis' party and Cissy Houston talked to her at around 3:15, TMZ reported. Clive Davis Party Houston was staying at the hotel to attend music industry executive Clive Davis' annual pre-Grammy bash. It is the same event where she was introduced to the record industry nearly three decades ago. Hours after her death, the party still went on but the scene was surreal. Whitney Houston's Death: Celebrities React The Beverly Hills crime lab was parked outside as paparazzi camped out waiting for Houston's body to emerge. Her Final Days Her final days were marked by questions about her sobriety. Houston's stay at the Beverly Hilton involved heavy partying, according to news reports. A duet with Grammy nominee Kelly Price at a party in a Hollywood nightclub earlier this week would become Houston's final performance. Houston was there with her daughter having a good time. But photos show a disheveled, bloated and agitated Houston leaving and she reportedly had blood dripping down her leg, scratches on her wrist and had to be escorted from the club. PHOTOS: Whitney Houston's Last Photos But the people who knew her said she was simply sweating from her performance. There was nothing wrong. She was singing, she was dancing, she was laughing, she was playingâ¦" Price said. I'm going to remember her just like that because that's the Whitney I always had the pleasure of being around. ABC News' Sheila Marikar, Cecilia Vega and The Associated Press contributed to this report.