Southwest Border Security:

Data Are Limited and Concerns Vary about Spillover Crime along the Southwest Border

GAO-13-175: Published: Feb 26, 2013. Publicly Released: Feb 26, 2013.

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Cary B. Russell
(202) 512-5431


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What GAO Found

The Federal Bureau of Investigation's (FBI) Uniform Crime Reporting (UCR) Program, the government's centralized repository for crime data, provides the only available standardized way to track crime levels in border counties over time. However, UCR data lack information on whether reported offenses are attributable to spillover crime, and have other limitations, such as underreporting to police. Also, UCR data cannot be used to identify links with crimes often associated with spillover from Mexico, such as cartel-related drug trafficking. Cognizant of these limitations, GAO's analysis of data for southwest border counties with sufficiently complete data show that, generally, both violent and property crimes were lower in 2011 than in 2004. For example, the violent crime rate in three states' border counties was lower by at least 26 percent in 2011 than in 2004 and in one other state lower by 8 percent in 2011 than in 2005.

Law enforcement agencies have few efforts to track spillover crime. No common federal government definition of such crime exists, and Department of Homeland Security (DHS) and Department of Justice (DOJ) components, including those with a definition, either do not collect data to track spillover crime, or do not maintain such data that can be readily retrieved and analyzed. However, several components collect violent incident data that could serve as indirect indicators of spillover crime. For example, GAO analysis of U.S. Customs and Border Protection (CBP) data show that, generally, assaults on agents between southwest border ports of entry were about 25 percent lower in 2012 than in 2006. State and local law enforcement agencies, except for one state agency, do not track what might be considered to be spillover crime because they lack a common definition and do not systematically collect these crime data in a way that can be used to analyze trends. Officials from 22 of 37 state and local agencies told GAO that they have limited resources to collect additional data. Since April 2012, DHS and the Texas Department of Public Safety have coled an effort to propose definitions and metrics for border-related crime by March 2013.

Law enforcement agencies have varying concerns regarding the extent to which violent crime from Mexico spills into southwest border communities. While DHS and DOJ threat assessments indicate that violent infighting between drug cartels has remained largely in Mexico, DHS assessments also show that aggressive tactics used by traffickers to evade capture demonstrate an increasing threat to U.S. law enforcement. Also, officials in 31 of the 37 state and local agencies stated that they have not observed violent crime from Mexico regularly spilling into their counties; nonetheless, officials in 33 of the 37 agencies were at least somewhat concerned, for example, for the safety of their personnel or residents.

Law enforcement agencies have undertaken initiatives to target border-related crime, including one effort to address violent crime spilling over from Mexico. For example, in October 2008, DHS developed a contingency plan for the possibility that a significant southwest border violence escalation may exceed DHS assets' ability to respond. In addition, officials from all state and local law enforcement agencies that GAO spoke with said their agencies had undertaken some efforts, either individually or in partnership with others, to combat criminal activities often associated with spillover crime, such as drug and human smuggling.

Why GAO Did This Study

Drug-related homicides have dramatically increased in recent years in Mexico along the nearly 2,000-mile border it shares with the United States. U.S. federal, state, and local officials have stated that the prospect of crime, including violence, spilling over from Mexico into the southwestern United States is a concern. GAO was asked to review crime rates and assess information on spillover crime along the border. Specifically, this report addresses: (1) What information do reported crime rates in southwest border communities provide on spillover crime and what do they show? (2) What efforts, if any, have federal, state, and select local law enforcement agencies made to track spillover crime along the southwest border? (3) What concerns, if any, do these agencies have about spillover crime? (4) What steps, if any, have these agencies taken to address spillover crime?

GAO analyzed crime data from all of the 24 southwest border counties from 2004 through 2011 and federal documentation, such as threat assessments and DHS's plans for addressing violence along the southwest border. GAO interviewed officials from DHS and DOJ and their components. GAO also interviewed officials from 37 state and local law enforcement agencies responsible for investigating and tracking crime in the border counties in the four southwest border states (Arizona, California, New Mexico, and Texas). While the results of the interviews are not generalizable, they provided insights. GAO is not making any recommendations. DHS provided comments, which highlighted border-related crime initiatives recognized by GAO.

For more information, contact Cary B. Russell at (202) 512-5431 or

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