SPRINGFIELD, Mo. -

The staff at the U.S. Medical Center for Federal Prisoners found an injured inmate unresponsive in his cell last Saturday afternoon.   They started life saving measures and sent the prisoner to a hospital, but he died Wednesday afternoon from his injuries. 

Kristie Bartlett, a prison spokeswoman, says investigators think Cyprian Adoh, 57, was a homicide victim.  He'd been at the prison hospital since April 26, 2011, after receiving a 70-month prison sentence in California for health care fraud.  Adoh  was at the medical center because he required dialysis.

The FBI is helping with the homicide investigation.   Bartlett says the Greene County Medical Examiner's Office will do an autopsy as part of the investigation.

The U.S. Medical Center for Federal Prisoners is on Kansas Expressway at Sunshine Street.  It had 1,035 male prisoners on Wednesday.  The center provides medical, mental health, and dental services.  

Bartlett said most of the prisoners live in housing units that they share with other prisoners; only a few are in single- or double-man cells.  Bartlett said she couldn't say what kind of housing unit Adoh lived in.  She also couldn't say what kind of injuries Adoh had.