Curiosity made me look this up, you were right except it happened in 1927. https://qconline.com/opinion/columnists/marlene_gantt/school-massacre-deadliest-in-history/article_1394e75c-6c79-5ba6-82bc-d305ed3e7be4.html
No guns needed.... though the perp was using a gun as the authorities arrived.
The criminal mind, sick mind, will MAKE/FIND a weapon. The weapon isn’t the problem.
And Biden, he doesn’t even want “non violent” criminals to be in jail! Heck, most violent criminals commit non violent crimes too.