Our Grants

Where Crime Guns Come From: Characterizing and Mapping Criminal Gun Markets


This study will analyze two decades of crime gun recovery and theft records for the state of California, linked to in-state handgun sales and transfers of ownership. This will provide a comprehensive and detailed study of the nature, structure and dynamics of California’s crime gun markets and the sources of firearms used in crime.




We will characterize criminal gun markets over time and across place in California; evaluate the impact of regulatory changes and law enforcement interventions aimed at disrupting the illegal supply of firearms; and identify purchaser, seller, and firearm characteristics and predictive factors associated with gun trafficking and criminal use.


Using records for more than 400,000 recovered crime guns and approximately 180,000 stolen firearms, merged with the state’s archives of identified firearm acquisitions, we will generate descriptive statistics and heat-map visualizations of criminal market indicators such as time-to-crime, out-of-state sales, and retailer point sources.

We will use interrupted time series and difference-in-difference models to assess whether supply-side law enforcement interventions such as crack-downs on point source dealers and regulatory interventions that tightened the licensing system for firearm dealers were associated with shifts in the structure and functioning of the illicit firearm market and firearm crime.

We will implement survival analysis to understand the occurrence and timing of crime gun recovery and identify significant risk factors, and use supervised machine learning algorithms to test the predictive capacity of the available data to identify high-risk purchasers, retailers and firearms, as well as the variables most predictive of firearm trafficking and criminal use.


While the specifics of this research will pertain to California, the broader conclusions and principles of analysis will be generalizable. The work will generate insight into crime gun sources and the transition of firearms purchased in the legal market to use in crime, improving our understanding of gun violence and helping to support new and better-informed policy and enforcement initiatives nationwide.

Published Research

  • Purchaser, Firearm, and Retailer Characteristics Associated With Crime Gun Recovery: A Longitudinal Analysis of Firearms Sold in California From 1996 to 2021

    View research Online summary
  • Trends and Sources of Crime Guns in California: 2010–2021

    View research

Investigator Bios

Hannah S. Laqueur is an assistant professor of Emergency Medicine at University of California, Davis. She holds a Ph.D. from Berkeley Law’s Jurisprudence & Social Policy program, a Masters in Biostatistics from University of California, Berkeley, and a Masters in Public Policy & Administration from Columbia University. She specializes in criminal justice policy and the economics of crime. Her research includes work on gun violence, drug policy, and machine learning methods to improve and evaluate decision-making in the justice system.

Grant Amount
Award Type
University of California, Davis
Hannah S. Laqueur, assistant professor of Emergency Medicine at University of California, Davis.
Focus Areas
Urban Gun Violence