Bratton said detectives have spoken to a number of doctors who have treated Jackson over the years and are looking into the singer's prescription drug history.

CNN: Source: Jackson family aware probe could be criminal case

Tommy has been interviewed and examined by doctors, detectives, police officers, and mental health experts, on repeated occasions, regarding the night of October 30, 1975.

CNN: Moxley Case: Excerpts from the Sutton Report