Operation Thumbs Down: An FBI Gang Takedown in South Central Los Angeles

This study examines whether a large-scale FBI-led gang takedown, known as Operation Thumbs Down, reduced violent crime in South Central Los Angeles. The operation specifically targeted the Rollin’ 30s Harlem Crips, a gang long associated with high levels of violence in the area. Unlike many earlier studies that focused on local police crackdowns, this research investigates the broader and longer-term effects of federal-level law enforcement interventions on neighborhood crime.

Research design

The takedown took place on August 29, 2013, as part of the FBI’s Enterprise Theory of Investigation (ETI) strategy. The ETI model emphasizes dismantling entire criminal organizations by targeting leadership, finances, and structure through federal prosecution and intelligence-led policing.

During Operation Thumbs Down, the joint FBI–LAPD task force conducted over 20 federal indictments and more than 40 arrests, combined with community clean-up and outreach activities in the weeks that followed. Although these social efforts were short-lived, they symbolized an attempt to combine enforcement with visible community restoration.

To evaluate the impact, we used seven years of LAPD violent crime data (January 2007 – October 2014) and compared the Rollin’ 30s’ area with a demographically and criminally similar control site — the Rollin’ 60s’ territory. We applied a Bayesian diffusion-regression state-space model using Google’s CausalImpact package to estimate what crime trends would have looked like had the operation not occurred. A surrounding “buffer zone” was also analyzed to test whether crime simply moved elsewhere, or whether benefits spread beyond the target area.

Key Findings

Violent crime fell by roughly 22% in the targeted area — an average reduction of about four violent crimes per month.
The reduction persisted for at least nine months following the takedown.
No crime displacement was detected. Instead, nearby streets experienced additional crime decreases, suggesting a diffusion of benefits rather than offenders moving to adjacent areas.
The reductions were statistically significant (p = 0.006) through June 2014.
Although the measurable impact faded after that point, overall crime levels remained lower than before the intervention.

The findings suggest that dismantling a gang’s leadership structure through an FBI task-force approach can yield meaningful short- to medium-term violence reductions. The outcome aligns with the ETI’s theoretical aim: reducing community harm by incapacitating key criminal networks.

While the study’s limited community outreach component — such as alley cleanups and resource fairs — likely had minimal influence on the overall decline, these gestures may have reinforced public confidence. The decline in crime was more plausibly linked to the incapacitation of the gang’s leadership and the resulting disruption of organized criminal activities.

However, the effect did not last indefinitely. By about nine months post-intervention, the statistical evidence of continued decline weakened. This finding underscores the importance of sustained engagement and the possibility that remaining or new offenders eventually filled the power vacuum left by the takedown.

More details

Limitations

The study was quasi-experimental, not randomized, and only 14 months of post-intervention data were available. We did not account for other law enforcement efforts active in the area at the same time. Additionally, there were no community-level surveys to measure resident perceptions or social impacts, limiting understanding of the broader community response.

Implications

Federal activity is often undertaken but rarely evaluated. Operation Thumbs Down provides rare empirical evidence that federal gang takedowns can reduce neighborhood violence beyond immediate arrests. We argue that combining targeted enforcement with community-focused efforts could extend these benefits and reduce the reemergence of gang activity. Future research should replicate this design with more cases, longer follow-up periods, and community feedback, to better understand both the scale and sustainability of such interventions.

Citation

The research was undertaken by Jerry Ratcliffe and colleagues, and these findings were published in an article in Policing: An International Journal. It is article number 64 here.

Ratcliffe, J. H., Perenzin, A., & Sorg, E. T. (2017). Operation Thumbs Down: A quasi-experimental evaluation of an FBI gang takedown in South Central Los Angeles. Policing: An International Journal, 40(2), 442–458. https://doi.org/10.1108/PIJPSM-01-2016-0004

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