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A Behavioral Study of American “Homegrown” Terrorists

NIJ-sponsored research provides evidence that individuals in the process of becoming dangerously radicalized exhibit predictable and detectable behaviors.
Date Published
October 8, 2018

There is no uniform profile of a jihadist terrorist, but individuals who become radicalized to terrorism tend to follow a predictable process. And through all phases of this process, individuals generally exhibit changes in behaviors and ideology that signal their descent into radicalization and potential violence.

According to research supported by the National Institute of Justice (NIJ), the process of becoming a jihadist terrorist is a lifestyle choice. It is associated with overt behavioral changes that are often, though not always, noticed by family or friends. This NIJ-supported research promotes a broader understanding of the signs and symptoms of radicalization and may assist law enforcement in developing better assessment protocols for intervention programs.

In this study, researchers examined detailed forensic biographies of 135 American jihadism-inspired homegrown terrorists. Biographies included court documents, online communications posted by terrorists, media profiles, and interviews with family members. All of the subjects were judged to have become radicalized while living in the United States.

One specific finding from the study is that a common precursor to radicalization is new-found religious fervor, followed by seeking out like-minded individuals or creating “pop-up” cells of co-believers by converting family members or friends to the cause. Initial contact may be through the internet, but the importance of real-life peer groups in driving further radicalization was highlighted by the finding that peer immersion nearly always preceded public expressions of a desire for action, either going abroad to fight or doing something in the United States.

Once an individual becomes involved with an extremist peer group or exhibits signs of advancing towards a greater commitment to the cause, radicalization generally speeds up.

Yet, researchers caution that it takes years to become a terrorist. Radicalization generally proceeds over the course of several years, although the pace of the radicalization has accelerated since 2010. Two causes for this are the jihadist recruiters’ use of social media to direct new followers and the Islamic State’s policy of taking in all volunteers.

Researchers suggest four policy recommendations:

  • First, a dynamic risk assessment protocol focused on tracing progressive extremism is feasible and may more reliably anticipate imminent risk of violent behavior than will unstructured protocols that use a list system.
  • Second, programs to counter radicalization to terrorism should focus on mobilizing families. Families are often a source of early warnings about risky behaviors, but many families misinterpret the signs of growing radicalization or ignore the risk.
  • Third, local law enforcement should develop outreach programs for Muslim community organizations and mosques. Many individuals committing terrorism have at some point in their radicalization trajectory come into contact with Muslim community institutions, and an increasing number have in recent years come to the attention of law enforcement through reports from Muslim community members and family. It is important that law enforcement continue to work with Muslim community organizations to develop trust and knowledge about the behaviors signifying extremism.
  • Finally, researchers suggested taking a long view on early prevention. This includes mainstreaming countering violent extremism (CVE) programming into middle school and high school. The focus in schools should be on preventing the development of cliques among students endorsing violent extremist belief systems. This means that school staff should understand what radicalization means and be trained to distinguish extremist practices from the expression of legitimate religious attitudes. The emphasis should be on behaviors associated with violent extremism—e.g. denigration of how most Muslims practice their faith and of other religions, and admiration for martyrdom and violence. Merging education and prevention programming on gangs and all types of violent extremist belief systems should be considered. Among other actions, researchers suggested including instruction about Islam. They also suggested education about online predators and internet-use hygiene.

About This Article 

The research described in this article was supported by NIJ grant number 2013-ZA-BX-0005 awarded to Brandeis University.

This article is based on the grant report “A Behavioral Study of the Radicalization Trajectories of American ‘Homegrown’ Al Qaeda-Inspired Terrorist Offenders” (pdf, 62 pages).

Date Published: October 8, 2018