California Code, Penal Code - PEN § 399.5

(a) Any person owning or having custody or control of a dog trained to fight, attack, or kill is guilty of a felony or a misdemeanor, punishable by imprisonment in a county jail not to exceed one year, or imprisonment pursuant to subdivision (h) of Section 1170 for two, three, or four years, or by a fine not exceeding ten thousand dollars ($10,000), or by both the fine and imprisonment, if, as a result of that person's failure to exercise ordinary care, the dog bites a human being, on two separate occasions or on one occasion causing substantial physical injury. No person shall be criminally liable under this section, however, unless he or she knew or reasonably should have known of the vicious or dangerous nature of the dog, or if the victim failed to take all the precautions that a reasonable person would ordinarily take in the same situation.

(b) Following the conviction of an individual for a violation of this section, the court shall hold a hearing to determine whether conditions of the treatment or confinement of the dog or other circumstances existing at the time of the bite or bites have changed so as to remove the danger to other persons presented by the animal. The court, after hearing, may make any order it deems appropriate to prevent the recurrence of such an incident, including, but not limited to, the removal of the animal from the area or its destruction if necessary.

(c) Nothing in this section shall authorize the bringing of an action pursuant to subdivision (a) based on a bite or bites inflicted upon a trespasser, upon a person who has provoked the dog or contributed to his or her own injuries, or by a dog used in military or police work if the bite or bites occurred while the dog was actually performing in that capacity. As used in this subdivision, “provocation” includes, but is not limited to, situations where a dog held on a leash by its owner or custodian reacts in a protective manner to a person or persons who approach the owner or custodian in a threatening manner.

(d) Nothing in this section shall be construed to affect the liability of the owner of a dog under Section 399 or any other provision of law.

(e) This section shall not apply to a veterinarian or an on-duty animal control officer while in the performance of his or her duties, or to a peace officer, as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2, if he or she is assigned to a canine unit.