Gunman Micah Johnson was killed using a Northrop Grumman tactical robot carrying one pound of C4 explosive in its arm following gun battle
The Dallas police department has defended its decision to use a robot to kill the gunman who fatally shot five of its officers, saying the controversial method was used only as a last resort.
Amid disquiet about the potential legal implications of the killing, the department also gave the first public details of the model of robot and type of explosive device they used against Micah Johnson, a 25-year-old army reserve veteran.
Johnson was killed late on Thursday by the explosion of a device carried toward him by remote control, after he was cornered by officers at a college parking garage. The action is thought to be the first killing by robot carried out by police in the US.
In a statement on Saturday, Dallas police said they had used a robot from the Remotec range (pdf), which is manufactured by the arms giant Northrop Grumman. The robot had been fitted with a claw and arm extension and was carrying approximately one pound (450g) of C4 plastic plus a detonating cord, they said.
Johnson opened fire on officers from the garage at the end of a peaceful demonstration. Five officers were fatally struck and seven others were wounded. The police said on Saturday they had no choice but to take out Johnson remotely after their efforts to talk him into surrendering ended unsuccessfully.
When all attempts to negotiate with the suspect, Micah Johnson, failed under the exchange of gunfire, the department utilized the mechanical tactical robot, as a last resort, to deliver an explosion device to save the lives of officers and citizens, the police statement said.
Some legal and civil liberties analysts said the unprecedented action threatened to disrupt the established legal order on homicides by law enforcement.
Elizabeth Joh, a law professor the University of California at Davis, told the Guardian last week that the use of killer robots by police officers raise all sorts of new legal, ethical, and technical questions.
Noting that use of deadly force by police officers was typically justified in terms of an immediate threat to the officer or others, Joh said: Its not clear how we should apply that if the threat is to a robot and the police may be far away.