By Kevin Lavery, KWMU
Potosi, MO – The victim is a functional unit manager at the maximum security prison southwest of St. Louis.
As of Monday afternoon, officials were withholding the victim's name and condition.
The alleged suspect is Roderick Nunley, convicted in 1989 of first degree murder, rape, kidnapping and armed criminal action.
Missouri Department of Corrections spokeswoman Angie Daly says all movement at the prison was immediately suspended.
"The institution is in lockdown, and an investigation is underway," Daly said. "It's my understanding that once the investigation is wrapped up and there's somebody that is pinpointed as the suspect of the crime, then that will be turned over to the local prosecutor, and it will be up to the local prosecutor then to file charges.
The victim was transported to an unnamed St. Louis hospital. The suspect is now being held in solitary confinement.
Officials are not saying what type of weapon was used, nor how the suspect obtained it.