Asimov's Aurora

The Third Law of Robotics states that a robot must protect its own existence, as long as such protection does not conflict with the First or Second Laws. After the diplomatic failures of the Spacer mission on Earth, Ambassador Ariel Burgess and roboticist Derec Avery are recalled to their home planet, Aurora. Their situation only worsens when they arrive, as they become suspects in another murder—one that could only have been committed by a non-human. On a world with a 20-to-1 robot-to-human population, is it possible a robot could have violated the Three Laws governing its behavior—and if so, why? Or is something far more sinister at work?