Finding who can be held to account after a six-year-old shoots a teacher

Rosalie List of Richneck elementary school at a vigil for Abby Zwerner, the teacher shot by a six-year-old student. Photograph: Billy Schuerman/AP

The shooting of a Virginia teacher by her six-year-old student last week left the town of Newport News and the rest of the US shaken and shocked.

Even in a country long used to the sort of school shootings that are rare in much of the rest of the world, the astonishingly young age of the shooter prompted a bout of public agonizing in the US about its gun violence problem.