A person who knowingly keeps a dangerous dog may be prosecuted for a felony or misdemeanor if the dog seriously injures another person as a result of negligence or letting it run loose.
For example, California Penal Code section 399 (as amended in 2001) states:
399. (a) If any person owning or having custody or control of a mischievous animal, knowing its propensities, willfully suffers it to go at large, or keeps it without ordinary care, and the animal, while so at large, or while not kept with ordinary care, kills any human being who has taken all the precautions that the circumstances permitted, or which a reasonable person would ordinarily take in the same situation, is guilty of a felony.
(b) If any person owning or having custody or control of a mischievous animal, knowing its propensities, willfully suffers it to go at large, or keeps it without ordinary care, and the animal, while so at large, or while not kept with ordinary care, causes serious bodily injury to any human being who has taken all the precautions that the circumstances permitted, or which a reasonable person would ordinarily take in the same situation, is guilty of a misdemeanor or a felony.
In People v. Berry (1991) 1 Cal.App.4th 778, a dog owner was convicted under the former version of section 399 because his pit bull (Willy) killed a young child (James Soto, 2 years and 8 months of age) who came onto the dog owner's property without the consent or knowledge of the dog owner. The attacking dog was one of three pit bulls. The court said that:
Willy was bred for gameness and wind and had a hard bite. Defendant specially trained Willy on a treadmill to condition him. Defendant told Richard Soto, Arthur Soto's brother, he would not fight Willy for under $500. He also warned him that Willy was "vicious and dangerous" and if he got loose he could "do a job" on certain people. He said he had a wedge to pry Willy's mouth open if he needed to. 1 Cal.App.4th at p. 781.
One of the defenses was that the dog was not "mischievous." The defendant relied on commonly accepted authorities that dogs and all other domesticated animals are not considered dangerous or mischievous as a matter of law. While the Court did not take issue with that proposition, it was noted that this particular pit bull was trained to participate in dog fights. As a result of that training, the Court held that the dog could be found to be mischievous, and the conviction was upheld. The Court wrote:
[W]e hold that 'mischievous propensities' as used in the statute means those propensities that may naturally pose a risk of harm or injury to others. (1 Cal.App.4th at p. 786.)
The Court also said:
Willy [the pit bull] was not a regular house pet. Rather, the jury found that defendant trained Willy and kept him as a fighting dog and that it was reasonably foreseeable that he might kill the victim. There also was evidence of Willy's fighting ability and defendant's warnings to others that Willy was dangerous to humans. (1 Cal.App.4th at p. 786.)
Note that the case does not stand for the proposition that a particular dog will be legally deemed mischievous simply because its breed is known to be unusually powerful and aggressive; the key fact in this case is that the particular dog was trained to fight.
The defendant raised Civil Code section 3342 (the dog bite statute) as a defense, saying that, because a trespasser cannot sue for monetary damages under 3342, the defendant had no duty to protect a trespassing child, and therefore the defendant could not be convicted under section 399. The Court disagreed, saying, "nothing in this civil statute suggests that it creates a defense in a criminal action based on the victim's status as a trespasser." (1 Cal.App.4th at p. 788.)
The defendant was found guilty of involuntary manslaughter, keeping a mischievous animal, keeping a fighting dog, and cultivating marijuana.
An unpublished decision in California, People v. Cornelio, holds that a conviction under Penal Code section 399 preempts a conviction under Penal Code section 192 for involuntary manslaughter. ("It is self-evident that a violation of section 399, subdivision (a) by keeping a mischievous dog with criminal negligence will commonly constitute a violation of section 192, subdivision (b) by the commission of the lawful act of keeping the dog, with criminal negligence. Thus, section 399, subdivision (a) preempts section 192, subdivision (b), and Cornelio's conviction under the latter section must be reversed.") In California, unpublished decisions cannot be cited as authority but are instructive as to how a court might rule in the future.
Sufficient evidence must be introduced to prove the elements of a crime. Although they cannot be cited, two unpublished decisions of the California Court of Appeal are instructive on a wide variety of evidence types: People v. Cornelio and People v. Gonzalez. These cases cannot be cited as authority, however.
In 2013, the United Kingdom called for public comments regarding a proposal to impose a life sentence on dog owners whose dogs kill a person. Read Owners of killer dogs may face life: Crackdown after 16 fatal maulings in eight years. Interestingly, the USA had 18 fatal maulings in the first 8 months of the same year, with pit bulls the killers in 16 of those cases, and yet there were no similar effort to increase the penalties here.