RALEIGH, N.C. (WNCN) — Law enforcement agencies posting on Facebook about crimes overreport those allegedly committed by Black suspects at a rate 25 percentage points higher than arrest records would suggest, according to a new study to be published Wednesday and co-authored by a Duke law professor.

The study highlights the way police departments and sheriff’s offices can shape the public perception of people suspected of committing crimes.

Law enforcement agencies increasingly use social media channels like Facebook to inform the public of crimes directly — with no external gatekeeper — as opposed to traditional print and broadcast media, which can filter those crime reports.

“What it suggests is that law enforcement agencies may be contributing, whether wittingly or unwittingly, to reinforcing and re-entrenching racial stereotypes about race and crime,” said Ben Grunwald, a professor at the Duke University Law School and one of the co-authors.

Researchers looked at roughy 10 million Facebook posts from the approximately 14,000 pages operated by law enforcement agencies from 2010-19, and ran them through an algorithm to sort out whether they describe crimes — and if they include a description of the suspect’s race.

It found that relative to local-arrest rates, Facebook users are exposed to posts that overrepresent Black suspects by 25-percentage points.

“When we say overrepresentation, what we mean is that an agency is posting more frequently about crimes allegedly committed by Black suspects, relative to the number of Black suspects arrested for those crimes in the same jurisdiction,” Grunwald said.

The study was published six days before an Election Day where crime is an issue up and down the ballot — from sheriff’s races to the push for North Carolina’s vacant U.S. Senate seat.

One consequence, Grunwald said, is that it might make people want harsher punishments.

“If you show people a story about a crime committed by a person of color, that can make them even more strongly positive toward criminal justice policies that are punitive,” Grunwald said. “That could be something operating in the elections coming up right now, given … how important criminal justice policy is, and the problem of rising crime rates in some areas leading up to the election.”

Researchers found the problem is more pronounced in places with higher shares of Republican voters or non-Black residents, though the study was not designed to explore the causes.

“It could be on the supply sides — it could be based on the preferences and motivations of the police officers who are operating these Facebook pages,” he said.

“Or it could be on the demand side, right? It could be based on what the police agency perceives the preferences and interests are of the people that are living in their area.”

A key question: What can people, now armed with this awareness and knowledge, do with it?

Grunwald said he hopes the study gives police agencies occasion to reconsider how they post about crime on Facebook and other social media platforms. He says in many cases, reporting the race of a suspect might not always be essential.

“My guess is that a lot of these agencies are just not thinking about the possible consequences of their posts,” he said. “And so just explaining to them or identifying to them this problem is we hope as we talk to more police agencies will have them reconsider how they’re posting.