[Ruy Dias de Bivar]

First school massacre was the Enoch Brown massacre in 1764 Pennsylvania.
https://pabook.libraries.psu.edu/literary-cultural-heritage-map-pa/feature-articles/enoch-brown-massacre-unmatched

Another happened in Hamilton TX in 1867.
https://texasescapes.com/TexasPersonalities/Ann-Whitney.htm

[Wallace T.]

There were a lot of killings involving Indian attacks on white settlers and white retaliations against the Indians. The Indians believed the white settlers were taking their native grounds. The whites were trying to establish farms and ranches for the livelihood of their families. This warfare did not end until the Battle of Wounded Knee, after which the Indian tribes stopped fighting.