WASHINGTON — Federal prison officials aren't reading all mail sent and received by convicted terrorists and other high-risk inmates, a security gap that could prove deadly, a Justice Department review concluded Tuesday. Moreover, prison investigators read less inmate mail now than a year ago at seven of 10 prisons surveyed by the Justice Department's inspector general. "Consequently, the threat remains that terrorist and other high-risk inmates can use mail and verbal communications to conduct terrorist or criminal activities while incarcerated," concluded the inspector general's report of U.S. Bureau of Prisons facilities. The mail investigation was spurred, in part, after three...