When Can Police Use a 'Bomb Robot' to Kill a Suspect?

Late Thursday night, Dallas police attached an explosive device to what's known as a "bomb-disposal robot," rolled it into an area where one of the suspected shooters was holed up, and detonated the bomb, killing him on the spot.

The move marked the first time that civilian police have used a robot to kill an American suspect on American soil, according to several legal and robotics scholars, raising major questions about the use of such machines in domestic stand-offs.