In the quarter century since the shocking events at Columbine High School in Colorado, there have been hundreds of school shootings, hundreds of articles and videos about police response times and tactics, and endless discussion about guns in the US. Headline findings: 96% of school shooters were male; 65% of the shootings were on high school campuses; 64% of the shooters were aged between 14 and 18, and therefore were too young to legally buy guns; 60% of shooters were former pupils. Mr Crow is calling for universal background checks on gun buyers, red flag laws that allow police to seize weapons from people who may be showing signs of behaviours associated with mass shooters, and an assault weapons ban - to make it harder to get the kind of guns that cause the most damage.