Police have already used a bomb disposal robot to kill a person [1] in the US.

The conversation they had shows slippery slope in action:

> After a brief silence, Commissioner Jesse Hsieh asked the next question: “Does the department plan on using a live round in the robot PAN disruptor?”

> The answer was immediately provocative. “No,” Daza-Quiroz said, before quickly pivoting to hypothetical scenarios in which, yes, just such a shotgun-armed robot might be useful to police.

[1] https://www.theguardian.com/technology/2016/jul/08/police-bo...