The New Jersey Office of Homeland Security and Preparedness distinguishes between ideological and non-ideological mass shootings in order to analyze mass shootings that could be linked to terrorism:
Ideological Mass Shooting
An incident in which an ideologically motivated offender(s) is engaged in killing or attempting to kill three or more victims, with a firearm, in one or more locations in close geographical proximity.
Non-Ideological Mass Shooting
An incident in which an offender(s) engaged in killing or attempting to kill three or more victims, with a firearm, in one or more locations in close geographical proximity. This excludes criminal activity and domestic violence.
The foundation of both these definitions were derived from the FBI's definitions of mass murder and active shooter. A three victim threshold was chosen based on the Investigative Assistance for Violent Crimes Act of 2012. This allows the Attorney General to assist in the investigation of mass killings and attempted mass killings.