Chicago

Somewhere in the district a microphone has picked up the percussive sound of a bullet and sent a signal, via California, to the station, which is where Kim Smith hears about it.

Ms Smith, a data analyst from the University of Chicago, works at one of the city's new Strategic Decision Support Centres, where data, technology, and old-fashioned police work are being combined in an effort to control a sudden surge in gun violence.

Chicago police spokesman Anthony Guglielmi (gooh-YEHL'-meeh) says 40-year-old Alprentiss Nash was killed Tuesday after arguing with his attacker.

He says police are questioning a person of interest.

Nash was convicted in the 1995 murder of Leon Stroud on Chicago's South Side, based on witness testimony. In 1997, he was sentenced to 80 years in prison.

The Chicago Crime Commission Tuesday formally restored the label days after Guzman slipped from a maximum-security facility through a mile-long tunnel.

The non-government group first named Guzman Public Enemy No. 1 in 2013 to highlight how his Sinaloa cartel dominates Chicago's drug trade. His hold on the title lapsed after his 2014 capture.

The only other figure to have the title was gangster Al Capone in 1930.