There is no such thing as murdering a robot. Robots are not alive. Murder is the killing of a human.
Regarding shooting equipment sent to spy on you.... I think you have every right to do what you need to do to protect yourself from invasive technology, so long as you are not breaking any laws you should expect privacy.
Oh, upon reading the article it is clear he is not being charged with 'killing' or 'murdering' the robot. He was simply charged with vandalism, which is understandable... It is also understandable that the police used the robot for surveilance considering this guy was threatening to the neighbors... But in the case of surveillance of people who are not in the commission of a crime I think that law enforcement needs to set rules of use, so not to impinge on personal liberty.