KNOXVILLE, Tennessee (AP) -- Two suspects in a case in which a young couple out for a date were carjacked and killed pleaded not guilty in federal court as prosecutors described their long criminal history. Lemaricus Davidson, 25, and Eric Boyd, 34, were arraigned separately. Davidson was charged with carjacking and firearms charges, and Boyd with being an accessory after the fact to the carjacking. Family members of victims Channon Christian, a 21-year-old University of Tennessee student, and her boyfriend Christopher Newsom, 23, wept as details of the carjacking and killings less than two weeks ago were recounted. The couple...