Final answer:
Between 1927 to 1931, there were at least 522 gang-related killings reported in Chicago, led by Al Capone's control of the liquor business through violence and the murder of his competition.
Step-by-step explanation:
Between 1927 to 1931 in Chicago, there were at least 522 gang-related killings reported in the newspaper headlines. Al Capone, one of the most notorious gangsters at that time, controlled the Chicago liquor business through violence, including the murder of his competition. While this number specifically focuses on gang-related killings, it does not provide a specific breakdown of how many were classified as 'gang murders'.