The body of Michael Jackson, who died Thursday, has been released by the Los Angeles County coroner's office.

Coroner Investigator Jerry McKibben says Jackson's body was returned to the singer's family Friday night and was moved to an undisclosed mortuary.

Jackson's body had been kept in its own crypt at the morgue under lock so that no pictures of the body would be leaked, a source told FOX News. Such a move rarely, if ever, happens.

PHOTOS: Click here for photos of Michael Jackson.

TOPIC: Click here for the latest on Michael Jackson.

The source told FOX News investigators conducting the autopsy were also surprised at how healthy Jackson was.

While he wasn't necessarily normal, he appeared to be stronger than they expected. Investigators were surprised to see significant scarring on his face, this being the first time they had seen Jackson without make-up.

He had bruises on his chest consistent with someone trying to revive him, but there were no obvious signs of a heart attack, which leads investigators to believe some sort of drug or drug combination caused either the heart to stop beating or the lungs to stop breathing.

Craig Harvey, a spokesman for the Los Angeles County coroner, said Friday there were no signs of foul play in the autopsy and further tests would be needed to determine Jackson's cause of death.

Jackson died Thursday afternoon at the age of 50 after being rushed from the Los Angeles area mansion where he was staying to UCLA Medical Center, where he was pronounced dead at 2:26 p.m.

No funeral plans have been made public.

The Associated Press contributed to this report.