Unless a dog mauls or kills someone—a very rare event—its owner probably won't be charged with a crime. (About 16 people die each year from dog attacks in the United States, according to the Centers for Disease Control and Prevention.) In such cases there is almost always evidence that the owner failed to take precaution despite knowing that the dog presented a grave danger to people, usually because the owner had trained the dog to fight or knew of previous unprovoked attacks or very aggressive behavior by the dog.
Depending on the circumstances and state law, an owner may be charged with anything from letting a vicious dog run loose to manslaughter or even murder. Here are some examples:
As state and local lawmakers have become more concerned about dog attacks, they have passed specific criminal laws aimed at people who allow their dogs to seriously injure people. Florida, for example, has made it a crime to own a dog that "aggressively attacks" someone and causes severe injury or death. If the dog hasn't already been found dangerous under the Florida dangerous dog law, the crime is a misdemeanor; if the dog has been declared dangerous, it's a felony. (Fla. Stat. § 767.13.) In Michigan, if a "dangerous dog" (defined as a dog that bites a person without provocation) kills someone, the owner is guilty of involuntary manslaughter. (Mich. Comp. Laws Ann. § 287.321.) In 1994, a woman whose two dogs had killed her two-year-old nephew, after she left him alone with the dogs, was sentenced to three years' probation under this law. (People v. Trotter, 209 Mich. App. 244, 530 N.W.2d 516 (1995).)
It's unusual, but local law may make anyone whose dog bites someone guilty of a crime. A woman in Topeka, Kansas, was charged with violating a city ordinance making it a crime to permit a dog to attack someone. The woman's dog rushed from her garage and bit a mail carrier. The dog owner was found guilty, despite her testimony that the mail carrier had "jammed her arm in the dog's mouth." (City of Topeka v. Mayer, 16 Kan. App. 2d 567, 826 P.2d 527, rev. denied (1992).)