Blue Line

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Preventing single actor extremist attacks: Part two

April 21, 2020  By Dr. Peter Collins and Dr. Alasdair Goodwill

In the March 2020 issue of Blue Line, we discussed that although it is difficult to predict single actor perpetrated terror attacks, we have become much better at understanding the behavioural, cognitive and emotional escalation of their path to violence. Prevention is possible if the focus is upon evidence-based and factual behavioural indicators of targeted violence, and threat management is employed to mitigate these behaviours of concern.1

To that end, we introduced the eight proximal warning signs of the Terrorist Radicalization Assessment Protocol (TRAP-18), a structured professional judgment instrument developed by Dr. Reid Meloy.2 This month’s article expands on that discussion by introducing the 10 distal characteristics of the TRAP-18.

Distal characteristics

1. Personal grievance and moral outrage – personal grievance is often associated with a major loss in love or work, triggering feelings of anger, humiliation, and reprehension. Moral outrage is typically a vicarious identification with a group which has suffered, even though the individual may have not shared the experience directly. Personal grievance and moral outrage are typically the first stages on the pathway to violence and may be likened to “the match that sparks the fire.”

2. Framed by an ideology – the presence of a belief system that justifies the extremist’s intent to act. Ideological framing may precede a personal grievance and it can often serve as an intellectual bridge to moral outrage and vicarious identification with the suffering group.

3. Failure to affiliate with an extremist group – the experience of rejecting or being rejected by a radical, extremist or other group with which the subject initially wanted to affiliate.

4. Dependence on a virtual community – use of the Internet, social media, chat rooms, emails, listservs, texts, tweets, etc., to propagate, reinforce and solidify an individual’s extremist and violent beliefs and can also facilitate learning (for example, planning and preparation).

5. Thwarting of occupational goals – a major setback or failure in a planned academic and/or occupational life course.

6. Changes in thinking and emotion – thoughts and the expression of thoughts become more strident, simplistic and absolute. Argument ceases and preaching begins. Persuasion yields to imposition of one’s beliefs on others. No critical analysis of theory or opinion and the dogmatic mantra, “don’t think, just believe,” is adopted. Emotions typically move from anger and argument to contempt and disdain for others’ beliefs, to disgust for the out-group, and ultimately a willingness to violently aggress against them. The use of violence becomes normalized and acceptable through self-righteousness and the pretense of superior belief. Humour is lost.

7. Failure of sexual-intimate pair bonding – the historic failure to form lasting sexually intimate relationships.

8. Mental illness – evidence of a major mental disorder by history or in the present. The ideology may help to reduce anxiety surrounding the mental disorder or utilize the symptoms to advance the attack (for example, suicidal thoughts and depression become motivations for martyrdom; delusions of grandeur to solidify commitment).

9. Creativity and innovation – evidence of tactical thinking “outside the box.” The planned terrorist act is creative (a major aspect has not been done before in contemporary times) and/or innovative (may be imitated by others).

10. Criminal violence – evidence of instrumental criminal violence in the subject’s past, demonstrating a capacity and a willingness to engage in predation for a variety of reasons, such as a history of armed robberies or planned assaults on others for material gain.

By way of analogy, Monahan and Steadman (1996) suggested that utilizing distal and proximal indicators of lone actor extremists for threat assessment and management, such as those of the TRAP-18, is similar to weather forecasting, in which one will watch a gathering storm in the distance and warn when there is potential for an imminent storm.

The presence of any cluster of distal characteristics constitutes the watch, signifying that the case should be continuously monitored and managed. The presence of any one proximal warning behaviour indicates a warning, signifying that the case should be actively risk managed. Accordingly, warning behaviours should compel a sense of urgency in those assessing and risk managing subjects of concern.3

As previously discussed, full training is required to utilize the TRAP-18 and this two-part series is provided simply as a brief overview of the TRAP indicators.

Further articles and empirical literature addressing the validity of the Terrorist Radicalization Assessment Protocol (TRAP-18) are available on Dr. Meloy’s website ( Online training can be accessed through


1. Meloy, J. R., & Hoffmann, J. (Eds.) (2014). International handbook of threat assessment. New York: Oxford University Press.
2. Meloy, J. R. (2017). The TRAP-18 manual version 1.0. Toronto: Multihealth Systems (
3. Monahan, J. & Steadman, H. (1996) Violent storms and violent people: how meteorology can inform risk communication in mental health law. American Psychologist 51, pp. 931-938.

Dr. Peter Collins is the operational forensic psychiatrist with the Ontario Provincial Police’s Criminal Behaviour Analysis Unit. He is also a member of the crisis/hostage negotiation team of the Toronto Police Service Emergency Task Force. His clinical appointment is with the Centre for Addiction & Mental Health in Toronto, and he is an associate professor with the University of Toronto. Dr. Collins’ opinions are his own and may not reflect the opinion of the OPP, University of Toronto, CAMH or his mother. Contact him at

Dr. Alasdair Goodwill is a clinical and forensic psychologist with over 20 years combined experience in behavioural investigative analysis, threat assessment, forensic risk assessment, and therapeutic services. He has a clinical practice and forensic consultancy and is an associate professor at Ryerson University. Contact him at

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