The Three Laws of Robotics (Isaac Azimov): A robot may not injure a human being or, through inaction, allow a human being to come to harm. A robot must obey orders given it by human beings except where such orders would conflict with the First Law. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.
As well, we are still a bit away from fully autonomous police robots killing people on the street.
But not that far.