Toxicology reports determined that Houston used cocaine "in the time period just immediately prior to her collapse in the bathtub at the hotel," said L.A. County Chief Coroner Craig Harvey. This finding has led to speculation that someone in the singer's entourage may have removed the drugs from the room since no traces of cocaine were found at the scene when authorities arrived.
"It's still an open investigation for us," Beverly Hills Police Lt. Mark Rosen told PEOPLE when asked if cocaine was found Houston's hotel room. "I can’t disclose any details about the investigation."
In addition to using cocaine immediately prior to her death, the coroner's office also indicated that cardiovascular disease was a contributing factor and there were signs of "chronic usage" of cocaine. According to MSN, chronic use of cocaine has been shown to cause atherosclerosis, or the formation of plaque inside blood vessels. Those plaques can eventually lead to severe narrowing of the heart vessels, causing heart attack, stroke, or fainting. If Houston experienced either of these while in the tub, it may have led to her accidental drowning.