WHoustonDead021112_X17crop230-1.jpgWhitney Houston's official cause of death has been ruled as "drowning and effects of atherosclerotic heart disease and cocaine use," according to the singer's toxicology report released Thursday.

The report also states: "Cocaine and metabolites were identified and were contributory to the death. Marijuana, Alprazolam (Xanax), Cyclobenzaprine (Flexeril), and Diphenhydramine (Benadryl) were identified but did not contribute to the death."

Houston was discovered unresponsive in the bathtub by a member of her entourage at the Beverly Hilton Hotel on Feb 11, and later pronounced dead at the scene. Preliminary media reports suggested that her death would not ruled a drowning and that no water had been found in her lungs, so the Coroner's findings come as a surprise to many.

It is possible that Houston could have suffered a heart attack that caused her to lapse into unconsciousness and drown.

The 48-year-old Grammy winner is survived by her only child, daughter Bobbi Kristina Brown. The 19-year-old is the sole heir to Houston's estate.