It’s no surprise that law enforcement agencies are increasingly using Facebook as a tool of surveillance. However, they can also use Facebook as a tool of unconstitutional censorship, according to a letter sent by the ACLU on behalf of a user permanently blocked from posting on a police department’s page.

The ACLU sent the letter last month to the Henry County Police Department in Georgia on behalf of Facebook user Will Sanders, who was blocked indefinitely from posting on the department’s page. The civil rights organization expressed concerns that the department was violating users’ First Amendment rights by censoring them. What’s more, the letter claimed Sanders filed an open records request and discovered the department had blocked up to 220 individuals.

“Though legal challenges to censorship on government social media sites are a relatively new phenomenon, at least one court has already found that targeted censorship on government Facebook pages open for public comment is unconstitutional,” ACLU of Georgia Legal Director Sean J. Young wrote.

Young also noted that the governors of Maine and Maryland are being sued by the ACLU for similar censorship, in addition to several other sheriffs’ departments. He also asked for the Henry County PD to respond within 30 days to the complaint.

While Facebook may present itself as a neutral platform, there’s no doubt it can be misused — even by government officials.