Chicago figured out they had to increase the number of police and arrest gang members to reduce homicides. This isn't rocket science, people. Police Raids on Chicago Gangs Stem Holiday Weekend Violence: City tries to get the most dangerous people off the street during the long weekend CHICAGO--A concerted effort here to reduce violent crime during the Memorial Day weekend appears to have paid off. Increased police presence across the nation's third-largest city and raids targeting gangs helped drive