columbine

FBI agents hunting a young Florida woman accused of threatening violence in the Denver area ahead of the 20th anniversary of Columbine said Wednesday she is "no longer a threat to the community."

FBI says a mass shooting is, “FOUR or more shot and/or killed in a single event [incident], at the same general time and location, not including the shooter.”

Unlike common criminals that may attack randomly or due to opportunity, terrorists place significant importance to certain historical dates.