Richelle Cooper (above), the ER doctor at UCLA Medical Center who pronounced Michael Jackson dead, took the stand in Dr. Conrad Murray's trial on Monday.

ConradMurrayTrialWeekTwoMonday230.jpgShe told the defense, "My assessment when he arrived was that he was clinically dead ... the resuscitation efforts would likely be futile. I felt comfortable pronouncing him." She said she never detected a pulse before calling his death at 2:26 p.m.

"Mr. Jackson died long before he became a patient I was personally responsible for," she said.

Next Dr. Thao Nguyen, a cardiologist working at UCLA that day, took the stand. She said Murray told doctors he'd only given Jackson Lorazepam -- nothing else -- and that he "did not have any concept of time." Nguyen says she asked Murray for time intervals when it came to the administering of medication, and that he was unable to answer.