Some are little more than a mechanical arm mounted onto a vehicle and equipped with a video camera and two-way audio communications, according to William Flanagan, a retired deputy police chief from New York's Nassau County who now does law enforcement and technology consulting. The most versatile robots can climb stairs and navigate other tight spots, such as this one made by Icor Technology.

DALLAS/HOUSTON/LOS ANGELES/WASHINGTON – When Dallas police improvised a bomb-carrying robot to kill a sniper, they also kicked off an ethical debate about technology's use as a crime-fighting weapon. In what appears to be an unprecedented tactic, police rigged a bomb-disposal robot to kill an armed suspect in the fatal shootings of five officers in Dallas. While there doesn't appear to be any hard data on the subject, security experts and law enforcement officials said they couldn't recall another time when police deployed a robot with lethal intent. The strategy opens a new chapter in the escalating use of remote-controlled and semi-autonomous devices to fight crime and protect lives. It also raises new questions over when it's appropriate to dispatch a robot to kill dangerous suspects instead of continuing to negotiate their surrender.

Dallas police respond after shots were fired during a protest over recent fatal shootings by police in Louisiana and Minnesota, Thursday, July 7, 2016, in Dallas. Snipers opened fire on police officers during protests; several officers were killed, police said. Dallas police respond after shots were fired during a protest over recent fatal shootings by police in Louisiana and Minnesota, Thursday, July 7, 2016, in Dallas. Snipers opened fire on police officers during protests; several officers were killed, police said. When Dallas police used a bomb-carrying robot to kill a sniper, they also kicked off an ethical debate about technology's use as a crime-fighting weapon.