In besieged Chicago, how police are tapping Big Data to try to curb gang violence.
The city has boosted foot patrols in high-crime areas and is adding again to a downsized police force. It's too soon to say whether that explains a 33 percent drop in the homicide rate – or whether the improvement can be sustained.
Chicago's surging murder rate is now four times that of New York. With drug cartels battling for turf and gang warfare turning chaotic, how can the Windy City get a handle on its homicides?