A serial killer beaten to death inside an Ohio prison died from massive head trauma.
An autopsy completed Friday shows Donald Harvey had several skull fractures and brain injuries.
Harvey was dubbed "Angel of Death" after a string of killings at hospitals in Cincinnati and Kentucky where he worked as a nurse's aide during the 1970s and `80s.
Investigators say an inmate is suspected in the attack, but no charges have been filed.
The Lucas County Coroner says the autopsy shows that no weapon was used in the attack.
Harvey died Thursday, two days after he was found in his cell at the state's prison in Toledo.
The 64-year-old in 1987 pleaded guilty to killing three dozen hospital patients but claims he killed others and couldn't remember how many.
