The NYPD went deep cover among Black Lives Matter activists during a protest in New York City and accessed text messages from leaders in the group, according to legal documents published by The Guardian.

The documents, obtained through a Freedom of Information Act lawsuit show the texts were passed between a number of undercover officers. They were primarily e-mails that show the officers had found their way into small groups of demonstrators to get information about the group’s location and planning in protests in November 2014 and January 2015.

“Die in & community convergence at Grand Central. FYI stock up on FREE earplugs — avail every night,” one message reads. “Convergence at Union Square begins in 15 Mins #ShutItDown,” another reads.

Keegan Stephan said that the disclosures show that the officers were able to blend into groups as small as seven individuals and obtain information that was never shared beyond a handful of people.

“It makes me think that some of these undercover officers were deeply embedded in our groups and that they were infiltrating our social networks, not just attending public demonstrations,” Stephan told the Guardian.

Another activist, Elsa Waithe, expressed dismay that police seemed to use trust among individuals who knew each other in order to gain access.

“That text loop was definitely just for organizers, I don’t know how that got out,” said Elsa Waithe, a Black Lives Matter organizer. “Someone had to have told someone how to get on it, probably trusting someone they had seen a few times in good faith. We clearly compromised ourselves.”

E-mails between the officers show them following the movements of protesters during a protest at Grand Central Terminal

The documents were ordered released in February, despite the NYPD’s argument that releasing them would interfere with their work.

But a lawyer who helped pursue the lawsuit said that the officers acted to infiltrate the group when there was no reason to do so.

“The documents uniformly show no crime occurring, but NYPD had undercovers inside the protests for months on end as if they were Al Qaeda,” attorney David Thompson told the New York Daily News. “This is not law enforcement, it is NYPD acting politically while wearing guns, and using the authority and secrecy the NYPD is granted as political weapons.”