Turns out that that massacre was not the worst such tragedy in US history. Nor is the access to firearms necessarily the cause or the root of the problem. In 1927, a man, apparently mad, murdered 45 people by blowing up a school in Bath, Michigan. For him, a gun was unnecessary.
Some excerpts from the story:
Across the world, newspaper headlines announced the shocking tragedy in the village with the unlikely name of Bath. The story competed for page one space with the Charles Lindbergh flight and massive floods on the Mississippi River. The New York Times story of May 19 read “MANIAC BLOWS UP SCHOOL, KILLS 42, MOSTLY CHILDREN.” The press struggled to find reasons for Kehoe’s bombing rampage, but of course, there were none. In the wake of such a tragedy, there is never an acceptable explanation. The Bath community was devastated. Its loss could not be measured in simple numbers. No one in the village escaped harm. Virtually everyone had lost a relative, friend, classmate, teacher.
A total of 38 children were killed, 7 teachers died and 61 others were severely injured. It was the worst school violence in [US] history.