This data set of more than 11,000 homicides from 1870-1930 is based upon a set of handwritten records kept without interruption by the Chicago Police Department, consistently, and with the same protocol and indexing system, over a sixty year period. The Chicago Police as an institution changed greatly during this period. Allegations of corruption alternated with periods of reform, while the general trend over the period was towards increased professionalization of the police.
