Whitney Houston was a chronic cocaine user who had the drug in her system when she drowned in a hotel bathtub, coroner's officials said after releasing autopsy findings that also noted heart disease contributed to her death.

The release of autopsy findings Thursday ends weeks of speculation about what killed the Grammy-winning singer on Feb. 11 on the eve of the Grammy Awards.

Houston was found submerged in the bathtub of her room at the Beverly Hilton Hotel and her death has been ruled as accidental. Several bottles of prescription medications were found in her hotel room, but coroner's officials said they were not in excessive quantities.

Beverly Hills police said in a statement there was no evidence of wrongdoing in connection with Houston's death.

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

Coroner's spokesman Craig Harvey says cocaine and its byproducts 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.

Coroner's officials said they also found traces of marijuana, Xanax and benadryl in her system.

Plaque in arteries

The singer also had buildup of plaque in her arteries that can restrict blood flow. Assistant chief coroner Ed Winter said the condition is common in drug users, though he said it wasn't clear whether Houston had a heart attack on the day she died.   "It just beats up their heart and they will go to use and they will have a heart attack," he said.  

Whitney Houston's full autopsy report may offer more clues about whether the singer suffered a heart attack before her drowning death, Winter added. The full report may include test results and physical descriptions of the singer's heart.

The exact amount of cocaine in Houston's system was not disclosed Thursday but will be contained in a full autopsy report to be released in about two weeks, officials said.

Cocaine use has been known to cause damage to the heart and could have caused Houston's death, said Dr. Michael Fishbein, professor of pathology at the David Geffen School of Medicine at UCLA.

He had no role in the investigation. He said a likely scenario was that Houston's cocaine use interfered with the normal function of her heart. 

"There's no reason to drown in a bathtub unless you're incapacitated," Fishbein said.

Family and friends said after Houston's death that they didn't believe she was still abusing drugs.

"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, wrote in a statement to The Associated Press on Thursday.

Houston died just hours before she was scheduled to appear at producer Clive Davis's pre-Grammy Awards bash.

The singer was buried in a New Jersey cemetery next to her father after an emotional four-hour funeral service that was attended by friends, family and superstars such as Oprah Winfrey, Tyler Perry, Alicia Keys, Mariah Carey, Mary J. Blige, Jennifer Hudson and Roberta Flack.

Houston, a sensation from her first, eponymous album in 1985, was one of the world's bestselling artists from the mid-1980s to the late 1990s, turning out such hits as I Wanna Dance With Somebody, How Will I Know, The Greatest Love of All and I Will Always Love You. But as she struggled with drugs, her majestic voice became raspy, and she couldn't hit the high notes.

Interest in her music has skyrocketed since her death, pushing her songs back onto charts and into heavy rotation on the radio.