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Justice

How to Uproot a 'Tree of Death'

Predictive tools can now track how a single shooting incident triggers a lethal cascade of gunshot violence—and predict who will be targeted next.
A Chicago police officer collects evidence from one of several shooting scenes over Fourth of July Weekend in 2015, when 9 people were killed in gun violence.
A Chicago police officer collects evidence from one of several shooting scenes over Fourth of July Weekend in 2015, when 9 people were killed in gun violence. Jim Young/Reuters

A young man who runs with the Black Disciples was shot in the foot in a dispute with rival Gangster Disciples on Chicago’s South Side, the New York Times reported late last year. Days later, two Gangster Disciples caught a bullet in a drive-by a block away. The day after that, the mother of a Black Disciple was shot in the foot, caught in the middle of more crossfire between the two gangs.

These were just a few of Chicago’s 4,368 shootings in 2016, but they’re telling: So much gun violence in American cities follows this tit-for-tat pattern of vendetta between people who know each other. What if there was a way to anticipate that and break the chain?