According to futuristic writings in the 1960s, robots would soon drastically reduce crime  With night vision and ability to detect the chemicals involved in ballistics, such robots could be programed to paralyze anyone roaming the street at night with a gun: virtually all criminals fit that description
These criminals would be incapacitated and thus unable to resist an easy arrest
Since police officers carry guns, the robots would incapacitate them just as efficiently as they incapacitate criminals.