Havoc broke out at a peaceful protest against police violence and racism in Dallas on Thursday evening when a sniper opened fire, shooting 12 officers and 2 civilians. Police cornered the suspect, now known to be Micah Johnson. Around 3 a.m., police reported that the sniper ... was killed by explosives delivered by a remote-controlled robot. We saw no other option but to use our bomb robot and place a device on its extension for it to detonate where the suspect was," said Dallas police chief David Brown. Experts say this is the first use of a robot to kill a suspect in the history of US law enforcement. Debate about Johnson's death is situated within a larger conversation about police militarization and why it has become a law enforcement trend. That question has been central to the Black Lives Matter movement. Militarized equipment, including this bomb-wielding robot, has become increasingly common in domestic police forces, as a result of the government's 1033 program that filters excess military equipment into domestic law enforcement departments. Joseph Pollini, a retired NYPD lieutenant commander, [said] the use of an explosive was more surprising than the use of a robot. "In my entire career I've never heard of using an explosive device to terminate someone," he says. "There is a huge concern about the weaponization of robotic platforms, as these technologies become more sophisticated and more autonomous, and weapons are actually quite easy to attach to them," both by civilians and police, he says.