The Worst Mass Murder in a school in U.S. history took place on May 18, 1927 which killed 45 people and injured 58. Most of the victims were children in second to sixth grades attending the Bath Consolidated School.
School board member Andrew Kehoe, upset by a property tax for a new school building which caused the foreclosure of his farm, set up a series of explosions in the Bath elementary school. That morning he killed his wife and set his farm building on fire. While fire fighters were arriving at the farm, an explosion destroyed the north wing of the school. As people gathered outside the school, Kehoe drove up and detonated a bomb inside his shrapnel-filled vehicle. During the rescue efforts, searchers discovered an additional 500 pounds (230 kg) of unexploded dynamite and pyrotol planted throughout the basement of the school's south wing. The bombings constituted the deadliest act of mass murder in a school in U.S. history.
The Worst Mass Murder in a school took place on September 1, 2004 killing 344 including 186 children plus additional 31 terrorists at School Number One (SNO) in the town of Beslan, North Ossetia Russia known as Beslan School Seige.
Packed into the school gym with wired explosives attached to the basketball goal