Close to five thousand people have died in federal prison since 2009.There are 100 federal prisons across the U.S. An NPR investigation found that a quarter of those deaths happened at one federal prison. Butner Federal Correctional Complex in North Carolina. Inmates have a constitutional right to health care. Being denied care is considered cruel and unusual punishment. But many of the sick inmates who wind up at Butner don't get the healthcare they are entitled to – and some end up dying. NPR's Meg Anderson tried to find out why.Email us at considerthis@npr.org.