I do not know the WHOLE story on this one, I am hoping that the sheriff's deputy in question had good reason to shoot the dog.  According to this story, eyewitnesses claim that he did not.

It seems that mid day Saturday, two dogs were running loose on Highway 171 near Longville when motorists called 911.  By the time deputies arrived, one of the dogs had been restrained, but the other was still loose.  At some point, one of the deputies shot and killed the second dog.

This news report (originally from KPLC in Lake Chuck) isn't very well-written, and many details remain unknown.  I REALLY hope that the deputy had a life-or-death reason to shoot this dog.

(Via KPLC)