[cimmanom]

IIRC there was a wave of school shootings in 1992-96, almost a dozen total; Columbine was the worst of them in terms of casualties, but in some ways just the culmination of a pattern. I don't know why you would start counting _after_ 1996.

[Torgo]

New York was putting metal detectors into schools in the 1980's. They were for gangs, but I guess a school shooting is a school shooting.