You missed one – a local one.
Jan 29, 1979, Brenda Spencer opened fire on Cleveland Elementary in San Diego. She killed 2 adults, and injured 8 children.
Stated reason: “I don’t like Mondays”. Basically she was bored and her dad had given her a Ruger the month before, for Christmas.
She was a trailblazer of the worst sort – this was the first school shooting.
Great Boomtown Rats song about it – but they wouldn’t sell the albumn in San Diego till 6 months after the release. (I had to go to LA to get a copy of the vinyl.)