WBEZ has an in-depth piece on stop-and-frisk, a practice used by police departments that has been ruled unconstitutional in New York City, and has just recently come under scrutiny in Chicago. A stop-and-frisk is a random encounter initiated by a police officer that escalates to a pat down for weapons. The ruling in the New York City case found that the NYPD's stop-and-frisk program disproportionately targeted minorities. The process of investigating stop-and-frisk practices in Chicago has proven to be fraught with obstacles. In 2011, the ACLU of Illinois filed a FOIA to look at the nature and number of stop-and-frisks performed by the Chicago Police Department. Unfortunately, stop-and-frisk encounters are not being recorded in the system implemented by the CPD, and the documentation gathered as a result of the FOIA request was subject to extensive redaction.