Some suggested keywords:
- Mass Shooting
- Public Shooting
- "public mass shooting"
- mass murder
- mass homicide
- mass killing
- multiple murder
- multiple homicides
- rampage shooting
- rampage killing
- active shooter
- mass casualty shooting incidents
The location of specific incidents (e.g. Columbine, U.S. Navy Yard) maybe used as keywords, as well as the names of specific perpetrators