On December 9, 2014, at 4:48 p.m., an internal email with the subject line, “Reminder for Tonight and this week: Do Not Advise Protesters That We Are Following Them on Social Media,” circulated among dozens of California Highway Patrol commanders. The message read: “A quick reminder … as you know, our TLO [Terrorism Liaison Officers] officers are actively following multiple leads over social media.” The note continued, “this morning, we found posts detailing protesters’ interaction with individual officers last night. In the posts, protesters are stating that we (CHP) were claiming to follow them on social media. Please have your personnel refrain from such comments; we want to continue tracking the protesters as much as possible. If they believe we are tracking them, they will go silent.”
In recent years, police agencies throughout the United States have scoured social media as part of criminal investigations. But the police are also watching social media to spy on political protesters, especially those they suspect will engage in acts of civil disobedience. During the recent Black Lives Matter protests, local and state police agents monitored protesters on social media and activist websites. Several hundred CHP emails obtained by the Express show that social media is now a key source of intel for the police when monitoring political protests.