All state-run and private prisons in Mississippi have been put on lockdown as officials investigate a conflict that left one inmate dead and two others injured.

The prisoner died Sunday after a “major disturbance” at South Mississippi Correctional Institution in Greene County, Mississippi Department of Corrections spokeswoman Grace Simmons Fisher said in a statement Tuesday.

Fisher said no staff members at the prison were hurt, but she could not provide other details about the disturbance because it is under investigation.

“Conditions at SMCI are under control,” she said.

It’s not unusual for all Mississippi prisons to be put on lockdown after a disturbance at one.

Terrandance Dobbins, 40, was the inmate killed Sunday.

He was serving a life sentence for a 1998 homicide conviction in Adams County and eight years for aggravated assault in Sunflower County. Fisher said an autopsy will determine how Dobbins died.

Three state prisons, three private prisons and 15 regional jails were put on lockdown and movement has been restricted within them to protect the public, staff and inmates, Fisher said.

The lockdown will continue indefinitely as authorities investigate the death.