Dr. Conrad Murray has pleaded not guilty to the involuntary manslaughter of the pop star, who died in June 2009 from an overdose of the powerful anesthetic propofol. Prosecutors said on Friday they wanted to call an additional medical expert at the trial to counter what are expected to be suggestions by Murray's defense team that the "Thriller" singer swallowed propofol by himself.

Murray's lawyers argued they needed more time to prepare to cross examine the new witness.