Dallas suspect wrote in blood on wall, taunted police during negotiations

The suspect in the deadly attack on Dallas police taunted authorities during two hours of negotiations, laughing at them, singing and at one point asking how many officers he had shot, the police chief said Sunday. Micah Johnson, a black Army veteran, insisted on speaking with a black negotiator and wrote in blood on the wall of a parking garage where police cornered and later killed him, David Brown told CNN's State of the Union. Johnson, who was apparently wounded in a shootout with police, wrote the letters "RB" and other markings, but the meaning was unclear. Investigators are trying to decipher the writing by looking through evidence from Johnson's suburban Dallas home, Brown said. The chief defended the decision to kill Johnson with a bomb delivered by remote-controlled robot, saying negotiations went nowhere and that officers could not approach him without putting themselves in danger.