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Mass Shootings: A Research Guide: Terrorism

The Problem of Definition Revisited

Once again, definitions are relevant to the study of terrorism's relationship to mass shootings. What qualifies as a terrorist act?

There is no single definition of terrorism, either within the U.S. or internationally. The rise of "lone wolf" terrorists, who may "self-radicalize" and have no clear ties to known terrorist organizations, further complicates attempts to define terrorist incidents. 

Examples of definitions:

For more sources on lone wolf terrorism, see this brief bibliography (PDF).

Data Sources

Mass Shootings and Terrorism

The San Bernardino incident of Dec. 2, 2015, was investigated by the FBI as a terrorist incident due to " indications of radicalization by the killers and of a potential inspiration by foreign terrorist organizations." 

The shooter in Orlando "Pulse" incident of June 12, 2016, claimed allegiance to ISIS, according to FBI reports

Within the U.S., whether certain other mass shooting incidents should be considered "terrorist" has been a subject of public debate. These include:  

  • Two incidents (Dallas, TX, July 7, 2016, and Baton Rouge, LA, July 17, 2016) involving black shooters who targeted police officers, in apparent retaliation against police shootings of black men. The Baton Rouge shooter appears to have espoused violent black separatism.
  • Emanuel African Methodist Episcopal Church, Charleston, SC  (June 17, 2015) -- shooting at a predominantly black church with a history of civil rights activism, committed by a  white shooter who claimed he hoped to start a race war
  • Planned Parenthood, Colorado Springs (Nov. 13, 2015) -- shooting at a clinic offering abortion services, committed by a shooter who referred to himself as "a warrior for the babies".
  • Chattanooga, TN (July 16, 2015) -- shooter targeted military recruiting offices and a military training facility and was said to have been "inspired" by terrorist propaganda
  • Oak Creek, WI (Aug. 5, 2012) -- shooting at a Sikh temple by a white supremacist 
  • Fort Hood, TX (Nov. 9, 2009) -- shooting at a military base by a military psychiatrist who expressed sympathy for radical Islamist organizations

Although bombs are perhaps more familiar as weapons of terrorism, notable terrorism-related mass shootings have taken place outside the U.S. in recent history. Selected examples:

  • Paris attacks of November 13, 2015 
  • Charlie Hebdo Paris attacks of January 7, 2015 
  • Nairobi, Kenya, shopping mall attack of September 21, 2013
  • Norway youth camp attack of July 22, 2011