Dallas Police Chief David Brown said on CNN Sunday the suspect in Thursday's deadly attack on officers, Micah Xavier Johnson, wrote the letters "R" and "B" in his own blood on the walls of the parking garage where he died. Police are still investigating the meaning of the message, which they believe Johnson inscribed before he was hit with a robot-operated bomb officers detonated to kill him.
Brown also defended the choice to use the bomb, which critics have suggested went too far in blurring the distinction between policing and warfare. "You have to trust your people to make the calls," he said. "We believe that we saved lives by making this decision."
Noting that investigators believe Johnson initially planned a larger attack well before this past week, Brown added, "I appreciate critics, but they're not on the ground, their lives are not being put at risk by debating what tactics to take."