2) An officer's first call of duty is to maintain peace and diffuse situations to avoid situations such as these. I failed to see any sort of attempt to diffuse this situation, only power and ego tripping.
3) Shooting their handgun is supposed to be their last resort, not first resort. Pepper spray or a tazer should have been their first resort.
All in all, this is nothing more than a brutal realization for Hawthorne PD to realize they need to step up their training. However, it seems they refuse to acknowledge they did anything wrong as they are stating they were trying to protect the owner as he was "defenseless" to his own dog because he was handcuffed. Unnecessarily handcuffed by the police over something that simply wasn't even illegal.
That being said, I'm a dog owner and am biased at this point.