What do we want police body cams to do?

Not even the Memphis police chief could dismiss the video footage of 29-year-old Tyre Nichols being fatally beaten by cops in early January. On the day before its public release, police chief Cerelyn Davis declared the attack “heinous, reckless and inhumane.”

Friday night, the rest of the country saw what she meant. Officials released four videos — three from officers’ body cameras and one from SkyCop surveillance footage — that showed Memphis police punching, kicking, and clubbing Nichols, who did not fight back. The videos showed Nichols crying out for his mom, captured a police officer saying, “I hope they stomp his ass,” and showed that it took over 25 minutes for him to receive medical attention. The Shelby County district attorney ultimately brought charges including murder, assault, and kidnapping against the five police responsible.

Memphis has nominally implemented police reforms over the past few years, including 2,000 body-worn cameras for police, which the city started rolling out in 2016.

Body cameras, which UK officers began experimenting with in 2005, took off rapidly in the United States in the 2010s, following several high-profile police shootings that garnered viral national attention from footage that citizens recorded on their cellphones. When a grand jury declined in 2014 to indict the police officer who killed Michael Brown in Ferguson, Missouri, Brown’s family asked the nation to join them “in our campaign to ensure that every police officer working the streets in this country wears a body camera.”