So, after making this very interesting statement? No data given. Great writing, Helen.
Yes, I'd hoped for a little more elaboration after that too.
I'm guessing that at least some of the mass killings of the '20s were caused by anarchist bombings. Probably a few Prohibition-related mob shootings in there, too. (St. Valentine's Day Massacre was in 1929.)
Also we have recently been reminded that the worst school mass murder in US history was committed in 1927, without guns.
"The Bath School disaster is the name given to three bombings in Bath Township, Michigan, on May 18, 1927, which killed 38 elementary school children, two teachers, four other adults and the bomber himself; at least 58 people were injured. Most of the victims were children in the second to sixth grades (711 years of age) attending the Bath Consolidated School. Their deaths constitute the deadliest mass murder in a school in U.S. history."