Mass murder

[3][4] In the United States, Congress defined mass murders as the killing of three or more persons during an event with no "cooling-off period" between the homicides.

[10] Many terrorist groups in recent times have used the tactic of killing many victims to fulfill their political aims.

In the Columbine shooting, the perpetrators, Eric Harris and Dylan Klebold, were able to murder 13 people, then commit suicide before the first SWAT team even entered the school.

While immediate action may be extremely dangerous, it could save lives which would be lost if victims and bystanders involved in the situation remain passive, or law enforcement response is delayed until overwhelming force can be deployed.

Such incidents can be, and have been even in recent decades, classified many different ways including "as a mass shooting; as a school shooting; as mass murder; as workplace violence...; as a crime involving an assault rifle; as a case of a mentally ill person committing acts of violence; and so on.

This Airbus A320 , registration D-AIPX, was destroyed while operating Germanwings Flight 9525 , having been intentionally crashed into the Alps by its co-pilot, killing all 150 people on board.
The funeral for sextuple axe murder victims in Huittinen , Finland in 1943, committed by Toivo Koljonen