Gun violence in Chicago, which peaked in 2016 when 764 people were shot and killed, continues to be a serious problem for the city. Most of the guns used in these homicides were not legally purchased or carried by the shooter. To better understand how and why individuals who are prohibited from owning firearms access, carry, and use guns, the University of Chicago Crime Lab conducted a survey in 2016 of 221 gun-involved males arrested in Chicago and detained in Illinois Department of Corrections (IDOC) prisons as part of a larger multi-method, multi-city study of underground gun markets. The survey, called The Chicago Inmate Survey of Gun Access and Use (CIS), seeks to inform efforts to interrupt the underground (or illicit) gun market that arms individuals who are legally prohibited from possessing guns. The CIS also explored perceptions of safety, cooperation with the police, and how individuals reduce their risk of arrest. To learn about the results of this study, click here for a fact sheet and here for the full report.