Cranberries singer Dolores O?Riordan died in March but it was unsure what was the cause of her death. It has now been revealed that the singer died of drowning, due to alcohol intoxication. According to Extra, the coroner said that O?Riordan?s death was a ?tragic accident.? A toxicology test showed the singer having alcohol content in her blood four times the legal driving limit. In addition, they found empty bottles of alcohol and prescription drugs in her room.