I read this short story a few weeks ago. It's pretty decent, if predictable. A backwater town on Mars takes delivery of an experimental police robot. The local police chief isn't too excited, but he allows the robot to do a few mundane tasks. All bets are off when the robot arrests a wanted man--who just happens to be in the employ of the town's local crime boss. That upsets the status quo. The showdown between the boss and the police robot predictably ends with a complete victory for the law.