The Bath School disaster, sometimes known as the Bath School massacre, was a series of violent attacks perpetrated by Andrew Kehoe on May 18, 1927, in Bath Township, Michigan, that killed 38 elementary schoolchildren and 6 adults and injured at least 58 other people.[Note 1] Kehoe killed his wife and firebombed his farm, then detonated an explosion in the Bath Consolidated School, before committing suicide by detonating a final device in his truck. It is the deadliest mass murder to take place at a school in United States history.
EDIT: I am impressed that this thread hasn't gone "south". I salute all who have commented, personally speaking, it has been very educational and enlightening.