Can the U.S. Bureau of Prisons safely house terrorists, as President Obama is suggesting, if it couldn't prevent Washington,D.C., inmates from tracking down and murdering an inmate inside the U.S. prison system? Washington Post columnist Colbert King asks that questions as he recounts the tale of the late Keith Barnes. Barnes was sentenced to a 15 year-to-life term after cooperating with authorities in providing evidence against co-defendants in a murder-robbery case.

After several transfers, he ended up at a U.S. penitentiary in Beaumont, Tx., arriving on May 6, 2005. He was murdered the next day by D.C. inmates, even though prison authorities were on notice that his life was in danger because of his testimony in the Washington case. Last month, a Beaumont federal jury found Joseph Ebron of Washington guilty of restraining Barnes while another inmate, Marwin Mosley, also of Washington, stabbed Barnes 106 times. Last week, Ebron was sentenced to die.