Leakage
Definition
Intentional or unintentional communication of intent to commit violence to a third party. One of TRAP-18's eight proximal warning behaviours and the most consistently documented in retrospective lone-actor case analyses. Can occur online (manifestos, forum posts) or offline (verbal disclosures to acquaintances or clinicians).
- Found in studied cases
- 77-93% of mass violence incidents according to Secret Service NTAC research
- Communication types
- Online (manifestos, posts, messages) or offline (verbal disclosures)
- Key framework
- One of eight proximal warning behaviors in TRAP-18
Common questions
What is leakage in threat assessment?+
Leakage is communication of violent intent to a third party, either intentional or unintentional, before an attack occurs. Research shows it's present in the vast majority of mass violence and active-shooter incidents studied, making it one of the most important concepts for professionals to understand.
How does leakage typically happen?+
Leakage can occur through many channels. Someone might tell acquaintances verbally about violent plans, post on online forums or social media, share manifestos, or even disclose intent to clinicians or mental health professionals. In some cases it's deliberate communication; in others it happens unintentionally.
Why is leakage important in threat assessment?+
Leakage is one of the most consistently documented warning behaviors in threat assessment research. It's operationally important because identifying leakage can provide early warning of planned violence and create opportunities for intervention before harm occurs.
Related terms
- BNS § 113 and UAPA
- BNS 2023 § 113 creates the general criminal offence of terrorist act in India. The Unlawful Activities (Prevention) Act 1967 (as amended...
- BNS 2023 § 113
- The Bharatiya Nyaya Sanhita 2023 terrorist act provision (replacing UAPA § 15 as the primary substantive offence for many terrorism prosecutions); does...
- BTAC (Behavioral Threat Assessment Center)
- The FBI unit that provides training, research, and case consultation on targeted violence threat assessment; operational successor to the Behavioral Threat Assessment...
- Channel Programme
- The UK's statutory civil intervention pathway for individuals assessed as vulnerable to radicalisation; operated through multi-agency Channel panels, placed on statutory footing...
- Channel Programme (UK)
- The referral and multi-agency assessment pathway within UK Prevent. Any public-sector professional can refer an individual; a Channel panel assesses vulnerability and...
- Disengagement vs Deradicalisation
- Disengagement: ceasing to participate in extremist activity without necessarily changing underlying beliefs. Deradicalisation: changing the beliefs and identity constructs that motivated extremism....
- ERPO (Extreme Risk Protection Order)
- A US civil-law mechanism (enacted in 21 states as of 2025) allowing courts to temporarily remove firearms from persons assessed as an...
- McCauley-Moskalenko Two-Pyramid Model
- Conceptual framework (Friction, 2011) distinguishing the opinion pyramid (distribution of extreme views) from the action pyramid (distribution of extremist behaviour). The two...
- Pathway-to-Violence Model
- A five-stage sequential model (grievance, ideation, research and planning, probing and preparation, attack) developed by Calhoun and Weston and elaborated by the...
- TRAP-18 (Terrorist Radicalisation Assessment Protocol)
- 18-indicator structured professional judgement instrument by Reid Meloy, Roshdi, Guldimann and Hoffmann (2014). Distinguishes 8 proximal warning behaviours (leakage, pathway, fixation, novel...
- TRAP-18 (Terrorist Radicalization Assessment Protocol)
- An 18-indicator threat assessment framework developed by Meloy and colleagues, comprising 8 proximal warning behaviours (pathway, fixation, identification, novel aggression, energy burst,...
- VERA-2R (Violent Extremism Risk Assessment)
- Structured professional judgement instrument by Elaine Pressman and John Flockton (2010, revised) for known extremist individuals in contact with the justice or...
Explained in these topics
- Extremism, Radicalisation and Lone-Actor ViolenceIntentional or unintentional communication of intent to commit violence to a third party. One of TRAP-18's eight proximal warning behaviours and the most consi...
- Threat Assessment for Mass Violence and Active-Shooter IncidentsThe communication, intentional or unintentional, of violent intent to a third party before an attack; present in approximately 77-93 percent of studied mass at...