Oklahoma Prisons Locked Down Following Inmate Stabbing in Northeastern Oklahoma

The prison yard at the El Reno Federal Correctional Institution in El Reno, Oklahoma, on July 16, 2015. Saul Loeb/AFP via Getty Images

HOMINY, Okla.—The Oklahoma Department of Corrections has locked down all prisons statewide and canceled all visitations following a stabbing at a medium security prison in northeastern Oklahoma.