(CBS/AP) Whitney Houston's death wascaused by accidental drowning, but heart disease and cocaine use were contributing factors, according to coroner's officials.

The announcement Thursday ends weeks of speculation about what killed the Grammy-winning singer on Feb. 11, at the age of 48.

Houston had cocaine in her system when she died, the coroner added. Marijuana, Xanax, Flexeril and Benadryl were also found in her system, but did not contribute to the singer's death. No foul play or trauma is suspected.

Houston was found submerged in the bathtub of her room at the Beverly Hilton Hotel, the day before the Grammy Awards.

Several bottles of prescription medications were found in her hotel room, but coroner's officials said they weren't in excessive quantities.

Coroner's spokesman Craig Harvey says cocaine metabolites were found in Houston's system, and it was listed as a contributing factor in her death. He says the results indicated Houston was a chronic cocaine user.