Cal. Food & Agric. Code § 31508

Upon the return day fixed in the summons, the judge shall proceed to determine whether the loss or damage to the livestock was caused by the dog. If he finds that it was caused by the dog, he shall notify the person that owns the dog or was in charge of it when the loss or damage was sustained to kill the dog. Failure of such person to kill the dog as directed renders the owner subject to the penalties which are prescribed in this division.