Want to know how to reduce gun crime? Look at Detroit.

People walk through downtown Detroit, Michigan, on April 3, 2024. The city has experienced a historic turnaround on crime that is both part of a national trend and the result of a transformation in the city’s policing. | Spencer Platt/Getty Images

Last year, Detroit saw its fewest homicides since 1966. Here’s how it did it — and how other cities can do the same.

In 2021, Detroit was in trouble.

The city, which already had one of the highest murder rates in the country,...