Whitney Houston's official cause of death was due to accidental drowning, the Los Angeles County coroner's office confirmed Thursday.

The singer, 48, was also found to have cocaine in her system. Contributing factors of her death included heart disease and cocaine use, an investigation found. The report also found that Houston had marijuana, Xanax, Benadryl and other medication in her system.

"There was water found in her lungs that indicated to us that she was alive when she was submerged underwater," coroner chief Craig Harvey tells PEOPLE. "According to our tests, the level of cocaine was not necessarily a lethal level of cocaine. But her death was complicated by chronic cocaine use and heart disease."

Coroner assistant chief Ed Winter says the circumstances of Houston's death come down to two likely scenarios.

"She could've passed out first due to the?intoxication from the cocaine, or she could've had a heart attack and then drowned," Winter tells PEOPLE. "It's probably one of those two scenarios."

Houston was found unresponsive and underwater in a bathtub at the Beverly Hilton Hotel on Feb. 11, a day before the Grammy Awards, and was pronounced dead at the scene soon afterward.

Coroner officials previously confirmed that prescription pill bottles were found in her room, but the number of pills were "not in alarming amounts."

滬江娛樂快訊：據(jù)報道洛杉磯警方今天公布了天后惠特尼·休斯頓的尸檢報告，稱休斯頓的死是由于溺水、心臟病以及毒品可卡因的使用造成。警方表示，惠特尼·休斯頓被發(fā)現(xiàn)時，其已經(jīng)在酒店浴缸溺水死亡，但“心臟病和可卡因的使用效果”，是她去世的促進因素。黑人歌唱天后惠特尼·休斯頓（Whitney Houston）于美國時間2月11日，被發(fā)現(xiàn)猝死于洛杉磯比佛利山莊的希爾頓酒店，年僅48歲。