Dr. Conrad Murray (C) is surrounded by his attorneys as he listens to testimony by Dr. Robert Waldman, an addiction specialist, during the final stage of Murray's defense case in his involuntary manslaughter trial in Los Angeles on October 27, 2011. Murray has pleaded not guilty and faces four years in prison and the loss of his medical licenses if convicted of involuntary manslaughter in Michael Jackson's death. UPI/Paul Buck/pool