America has been stunned by the ambush of white police officers by at least one sniper in Dallas, who hunted down and killed five police officers and wounded seven more along with two civilians. In distressing images captured by a member of the public Micah Xavier Johnson, 25, a former army reservist who did one tour of duty in Afghanistan is seen running amok before being cornered by police and killed. Attempted negotiations before his death failed, and he was killed with an explosive charge … The head of the Dallas police department has said a suspect involved in an armed stand-off with authorities, admitted wanting to kill white people, especially officers. Chief David Brown said the alleged gunman, who was killed after a police robot detonated an explosive device and has been identified as 25-year-old Micah Johnson by US media, was upset about the killing of black people by police.