Unless he accidentally discharged his weapon, it wasn't a mistake. He purposefully shot a dog for barking at him in its own yard. Even if he had gone to the *right* house, it wouldn't be fine shooting that sex offender's dog for barking on its owner's private property.
Do you think that any police officer should be able to pull up to any house and execute family pets and not be disciplined unless the owners can produce definitive evidence of a significant error related to the identification of the address?