A false flag is a covert operation event, usually perpetrated by a group belonging to or allied with our own government. It is designed to control populations through fear via a manufactured enemy; and often results in a mass-casualty deaths. Some of these events use crisis actors as victims, which means that there are no real casualties, though it is staged to seem like it.
The false flag formula follows a few simple rules:
Drills. There are always military drills, or police drills or fire brigade drills on the day of the event at a nearby location. This is no small feast and actually takes some major planning and coordination.