Two things stand out to me on this. A pit bull came at the officers. They do not know if it is friendly or not and shot at it. The second thing is this guy was a resident of Mexico. Was he here illegally? If so he may have had a gun to keep from being deported by the police. There is a lot of unanswered questions that I even have towards the justification of this shooting.
KN,
He worked for a city in Tennessee. Although it's possible to be an illegal and still work for a city it's darn hard. He was probably either a naturalized citizen or a long term resident green card holder. This one sounds fishy, although I admittedly don't have all the facts.