good evening. there has been another mass shooting in this country. this time close to the center of our government in washington, d.c., not far from the u.s. capitol. gunfire erupted this morning inside the washington navy yard, a complex of buildings dating back to the late 1700s. tonight, at least 12 people are dead. the police say another dozen are injured. seven minutes after the first call to 911, the first police officers rushed in. there were numerous gun battles, apparently, inside one of the buildings before the gunman could be taken down. he has been identified as aaron alexis, a military contractor and former naval reservist from texas. now this ranks with the shootings in ft. hood, texas, and aurora, colorado, in terms of size, scale and death toll. the shooting brought much of d.c. to a stand still. flights grounded, schools locked down. even the u.s. senate locked down because the u.s. capitol is just a mile and a half away from the navy yard and building 197 w