The pop star died in 2009 at the age of 50. His personal physician, cardiologist Dr. Conrad Murray, is serving four years in prison for involuntary manslaughter for administering lethal levels of propofol and sedatives to Jackson in an effort to help the insomniac sleep as he prepared for a high-profile concert residency in London.
Jackson's family is suing AEG, the organizers of the shows, for the singer's wrongful death.
The lawsuit alleges the company was at fault because it failed to hire an appropriate physician for Jackson, then neglected to supervise him properly.
AEG has maintained Jackson hand-picked Murray and kept his treatment for sleeplessness a secret.
CNN said Dr. Christopher Rogers, the deputy medical examiner who conducted Jackson's autopsy, testified in his wrongful-death trial this week.
"There was no indication from the autopsy that there was anything anatomically wrong with him that would lead to premature death," Rogers said, adding the musician displayed no signs of being addicted to street drugs.
CNN said the testimony is important because if the jury faults AEG for Jackson's death, his expected lifespan will be used to calculate damages.