Whitney Houston, whose naturally pure voice propelled her to record-shattering pop stardom, died in California today. She was 48.

The cause of the superstar's death was still being investigated, said Lt. Mark Rosen of the Beverly Hills Police Department. He said the singer was pronounced dead at 3:55 pm in the Beverly Hilton Hotel, where she had been a guest.

Rosen said there were no obvious signs of criminal activity and that the investigation would be turned over to the coroner's office. He said authorities received an emergency call from an unidentified person in Houston's entourage and responded within two minutes, but were unable to resuscitate her.

The six-time Grammy winner and actress had a roller coaster career that saw her soaring to the top of the charts and into the Guinness Book of World Records as the industry's "most awarded female artist of all time," then battling drug addiction and plummeting in a public fall from grace before battling her demons and rising once again.

Rolling Stone magazine once called Houston "the greatest female voice of her generation."

Houston died on the eve of the Grammy Awards, where producers and performers are no doubt scrambling to put together a tribute to one of their own. Houston had been preparing to attend tonight's annual pre-Grammy party of Clive Davis, the music mogul who discovered her.

The music icon's Billboard hits include "Saving All My Love for You," "How Will I Know?" "Greatest Love of All," "I Will Always Love You" and "Where Do Broken Hearts Go?"

Houston was the daughter of gospel singer Cissy Houston, the cousin of 1960s pop singer Dionne Warwick and the goddaughter of Aretha Franklin.

In addition to her numerous hit songs, Houston starred in films that included The Bodyguard, Waiting to Exhale and The Preacher's Wife. She had been set to return to the big screen in August in the musical drama Sparkle.

Houston was divorced from R&B singer Bobby Brown, with whom she had a tumultuous marriage. The two have a daughter, Bobbi Kristina.