Whitney Houston, 48, died by drowning in the bathtub of her Beverly Hilton Hotel room, but chronic cocaine use and heart disease were likely contributing factors in her death, coroner's officials said Thursday upon releasing an autopsy report.

"We are saddened to learn of the toxicology results, although we are glad to now have closure," Patricia Houston, the singer's sister-in-law and manager, said in a statement.

Houston's body was found on February 11, the night before the Grammy Awards were held in Los Angeles. Her death was ruled accidental.

Toxicology results also showed Houston had marijuana, Xanax, the muscle relaxant Flexeril and Benadryl in her system. It was not clear whether Houston suffered a heart attack before drowning, Assistant Chief Coroner Ed Winter said.

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