Officials in the eastern U.S. state of Maryland are investigating the death of a high-profile prisoner detained on suspicion of killing a police officer.

Ronnie White (image provided by the Prince George's County Department of Corrections, 28 Jun 2008)

Federal officials are investigating possible civil rights violations in the death of 19-year-old Ronnie White, who was found strangled in his maximum-security cell in the town of Upper Marlboro on Sunday.  

Prison officials said he had been separated from other inmates.  Seven guards and an undisclosed number of supervisors had access to him.  Officials are also investigating whether anyone from outside the prison system had access to him.

The head of the Prince George's county government, Jack Johnson, has said police are not suspected in the prisoner's death.  Johnson told a news conference Monday that society will fall apart if there is vigilante justice.

White was charged with first degree murder in the death of a police officer Friday.  The policeman was run over and killed by a truck allegedly driven by White.  

The attorney for White's family said his relatives were not informed of White's death until hours later.

The corrections facility where White was held has had other problems recently, including criminal actions by guards and the disappearance of guns from the armory.

Prince George's County is just outside Washington, D.C.