An initial autopsy report stated there were no signs of trauma and the Los Angeles County Coroner's Office determined "diabetic ketoacidosis", caused by a lack of insulin which can lead to a diabetic coma, was the cause of her demise.

No illegal drugs were found in Casey Johnson's system, although the autopsy report states she has a history of "possible excess use of (drowsy cold medication) NyQuil", reports TMZ.com.