Los Angeles (CNN) -- The emergency room doctor who declared Michael Jackson dead testified Monday in the involuntary manslaughter trial of Dr. Conrad Murray that there was no way doctors could have revived the pop icon after he arrived at the hospital. Dr. Richelle Cooper testified Friday that Murray never told her that he had given Jackson the surgical anesthetic propofol before he stopped breathing, but she said Monday it would not have made a difference if he had because Jackson "had died long before." "It is unlikely with that information that I would have been able to do something different that would have changed the outcome," Cooper said.
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NEW: First of three Murray girlfriends takes the witness stand Monday
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Doctor testifies Jackson couldn't have been saved even if Dr. Murray had told about propofol
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Balloon in Jackson's heart was "to prepare Dr. Murray mentally to accept" his death, doctor says
The timing of the phone call is key to the prosecution's time line of when @placeholder realized his famous patient was dying.