Investigating terrorist use of improvised explosive devices in the United States: Evidence from US federal court cases, 2009–2024

Understanding terrorist use of improvised explosive devices (IEDs) in the United States.

Abstract

Terrorist use of improvised explosive devices (IEDs) remains a persistent and evolving threat within the United States. Until now, few data collection and analysis efforts have focused on the systematic capture of terrorist bombing plots and attacks. Filling this evidence gap, this research note presents and analyses an original dataset of US federal charges associated with terrorism-related IED incidents in the United States observed from 2009 through 2024. The data features 110 related cases, the analysis of which indicates a sample peak in the use of IEDs in terrorist incidents occurred in 2024. Incidents are not siloed to a specific region within the US, but involve cases from coast-to-coast, with crowded spaces remaining the most prominent target. The most common form of device employment observed across the dataset is the person-borne IED, primarily involving pipe bombs and pressure cooker IEDs. Eighty percent of the incidents recorded in the sample were thwarted by intelligence and law enforcement professionals – the remainder either failed due to technical mistakes or were successful. The research note describes notable sources of change in IED threats over time and identifies emerging trends in the methods by which US-based terrorists may continue to utilise IEDs in their efforts to cause death, harm, and destruction. It concludes with implications for theory, study, and practice.

Eighty percent of the incidents recorded in the sample were thwarted by intelligence and law enforcement professionals – the remainder either failed due to technical mistakes or were successful.

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