SAN FRANCISCO >> San Francisco police will stop releasing the mug shots of people who have been arrested unless they pose a threat to the public, as part of an effort to stop perpetuating racial stereotypes, the city’s police chief announced today.

San Francisco Police Chief Bill Scott said the policy, which goes into effect immediately, means the department will no longer release booking photos of suspects to the media or allow officers to post them online.

Booking photos are taken when someone is arrested. They are often made public whether or not the person is prosecuted for the alleged crime, which undermines the presumption of innocence and helps perpetuate stereotypes.

Jack Glaser, a public policy professor at the University of California Berkeley who researches racial stereotyping and whose work Scott consulted, said data shows Black people who are arrested are more likely to have their cases dismissed by prosecutors.

But the mug shots live on.

Numerous websites post photos of mug shots online, regardless of whether anyone was convicted of a crime, and then charge a fee to those who want their photo taken down. The phenomenon prompted California’s attorney general to charge one of the biggest operators with extortion, money laundering, and identity theft.

That contributes to Americans making an unfair association between people of color and crime, Scott said.

“This is just one small step but we hope this will be something that others might consider doing as well,” he said.

Large cities like Los Angeles and New York already have policies against releasing booking photos but make exceptions. For example, the New York Police Department, the nation’s largest, releases information on arrests but doesn’t put out mug shots unless investigators believe that will prompt more witnesses to come forward or aid in finding a suspect.

In San Francisco, the only exceptions will be if a crime suspect poses a threat or if officers need help locating a suspect or an at-risk person, Scott said. Under the policy, the release of photos or information on a person who is arrested will also require approval from the police department’s public relations team.