Max Rust, Scott Calvert and Shibani Mahtani:

Murder in America is deeply local.

Homicides in the U.S. rose about 9% last year, according to the Federal Bureau of Investigation, and more than one-third of the increase was concentrated in neighborhoods where just one-third of Chicago residents live. Meanwhile, improvements in areas where 30% of Los Angeles residents live accounted for one quarter of the 13% drop in U.S. murders between 2002 and 2014.

The Wall Street Journal analyzed the locations of thousands of homicides in four cities: Chicago and Baltimore, where violence has risen to or near 1990s levels in the past two years; and Los Angeles and Washington, D.C., where meaningful declines in violence have been sustained since the 1990s.