Esperanza Spalding sings as a portrait of Whitney Houston is displayed on the screen during the memorial segment at the 84th Academy Awards in Hollywood, California, February 26, 2012.[Photo/Agencies]

Pop star Whitney Houston died of accidental drowning due to the effects of cocaine use and heart disease, a Los Angeles County coroner's spokesman said on Thursday.

The 48-year-old singer, who spent years battling addiction to drugs including cocaine, was found submerged in the bathtub of her Beverly Hills hotel room on February 12, the eve of the Grammy Awards.

An autopsy into Houston's death found that the cause of death was accidental drowning with atherosclerotic heart disease and cocaine use listed as contributing factors, Los Angeles County Coroner's spokesman Craig Harvey said.

Harvey said toxicology tests also turned up marijuana, an anti-anxiety medication, a muscle relaxant and an anti-histamine in Houston's system.

Those drugs were not found to have contributed to her death, and no trauma or foul play were suspected, the coroner's office said. A final report was expected to be made public within two weeks.

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

Houston soared to the top of the pop charts in the 1980s, best known for a string of hit songs including "I Will Always Love You." But her career declined as she battled personal issues that included drug addiction.

Patricia Houston told Oprah Winfrey in an interview this month that she had believed the pop star's worst days of drug abuse were behind her.

Members of the family told Winfrey that Houston was found face down and naked in the bathtub, and that attempts by her staff to revive her proved fruitless.

Houston was last in rehab in May 2011. But celebrity media reported that she was seen drinking heavily and behaving erratically in the three or four days before her death.

Sales and downloads of Houston's best-known songs, including "Saving All My Love for You" and "My Love is Your Love" soared around the world after her death.