LOS ANGELES — Whitney  Houston, who ruled as pop music's queen until her majestic voice and  regal image were ravaged by drug use, erratic behavior and a tumultuous  marriage to singer Bobby Brown, died Saturday. She was 48.
Beverly Hills police Lt. Mark Rosen told reporters outside the  Beverly Hilton that Houston was pronounced dead at 3:55 p.m. in her room  on the fourth floor of the hotel. Her body remained there and Beverly  Hills detectives were investigating.
"There were no obvious signs of any criminal intent," Rosen said.
Houston's publicist, Kristen Foster, said the cause of death was unknown.
Rosen said police received a 911 call from hotel security about  Houston at 3:43 p.m. Saturday. Paramedics who were already at the hotel  because of a Grammy party unsuccessfully tried to resuscitate the  singer, he said.
What was Whitney Houston's best song?
Houston's end came on the eve of music's biggest night — the Grammy  Awards. It's a showcase where she once reigned, and her death was sure  to cast a heavy pall on Sunday's ceremony.
Her longtime mentor Clive Davis was to hold his annual concert and  dinner Saturday, and a representative of the show said it would proceed.
Producer Jimmy Jam, who had worked with Houston, said he anticipated  the evening would become a tribute to her, and he expected there to be  one at the Grammys as well.
Houston was supposed to appear at the gala, and Davis had told The  Associated Press that she would perhaps perform: "It's her favorite  night of the year ... (so) who knows by the end of the evening," he  said.
   Video: Sharpton mourns loss of 'talented' Houston  (on this page) 
Houston had been at rehearsals for the show Thursday, coaching  singers Brandy and Monica, according to a person who was at the event  but was not authorized to speak publicly about it. The person said  Houston looked disheveled, was sweating profusely and liquor and  cigarettes could be smelled on her breath.
Two days ago, she performed at a pre-Grammy party with singer Kelly Price.
The Rev. Al Sharpton said he would call for a national prayer Sunday  morning during a service at Second Baptist Church in Los Angeles.
"The morning of the Grammys, the world should pause and pray for the  memory of a gifted songbird," Sharpton said in a written statement.
  Story: Stars react to Whitney Houston's death  
In a statement, Recording Academy President and CEO Neil Portnow said  Houston "was one of the world's greatest pop singers of all time who  leaves behind a robust musical soundtrack spanning the past three  decades."
"Her powerful voice graced many memorable and award-winning songs,"  Portnow said. "A light has been dimmed in our music community today, and  we extend our deepest condolences to her family, friends, fans and all  who have been touched by her beautiful voice."
At her peak, Houston was the golden girl of the music industry. From  the middle 1980s to the late 1990s, she was one of the world's  best-selling artists. She wowed audiences with effortless, powerful, and  peerless vocals that were rooted in the black church but made palatable  to the masses with a pop sheen.
Her success carried her beyond music to movies, where she starred in hits like "The Bodyguard" and "Waiting to Exhale."
   Video: Whitney Houston reportedly dies of unknown cause  (on this page) 
She had the perfect voice and the perfect image: a gorgeous singer  who had sex appeal but was never overtly sexual, who maintained perfect  poise.
She influenced a generation of younger singers, from Christina  Aguilera to Mariah Carey, who when she first came out sounded so much  like Houston that many thought it was Houston.
But by the end of her career, Houston became a stunning cautionary  tale of the toll of drug use. Her album sales plummeted and the hits  stopped coming; her once serene image was shattered by a wild demeanor  and bizarre public appearances. She confessed to abusing cocaine,  marijuana and pills, and her once pristine voice became raspy and  hoarse, unable to hit the high notes as she had during her prime.
"The biggest devil is me. I'm either my best friend or my worst  enemy," Houston told ABC's Diane Sawyer in an infamous 2002 interview  with then-husband Brown by her side.
It was a tragic fall for a superstar who was one of the top-selling  artists in pop music history, with more than 55 million records sold in  the United States alone.
   Slideshow: Whitney Houston, 1963-2012  (on this page) 
She seemed to be born into greatness. She was the daughter of gospel  singer Cissy Houston, the cousin of 1960s pop diva Dionne Warwick and  the goddaughter of Aretha Franklin.
Houston first started singing in the church as a child. In her teens,  she sang backup for Chaka Khan, Jermaine Jackson and others, in  addition to modeling. It was around that time when music mogul Clive  Davis first heard Houston perform.
"The time that I first saw her singing in her mother's act in a club  ... it was such a stunning impact," Davis told "Good Morning America."