The aim of this article is to show difficulties arising when courts judge the negligence of dog owners in absence of precise legislation and typical precedents. We analyze the elements of a crime in two cases where children were objects of canine aggression, and show how the courts constructed the issue of dog owners’ negligence. In Case 1 the Court of Appeal found that a foster parent was not negligent when leaving a boy with specific needs alone with a heavily built dog that then repeatedly bit the boy to death despite the owners attempt to pull away the dog. The court also ignored the signs of substandard animal husbandry including previous severe incidents where the dog owner also was injured. In Case 2, the Court of Appeal instead found that the breed of the dog also matter, and that not even adult presence is enough to protect a child from dog attack. Because both the child and the dog could behave unpredictably, continuous observation and supervision was required. In both cases, measures to prevent the incident were available and would have been easy to carry out.