Smartphones have turned virtually everyone into a filmmaker. This has meant that many people’s reaction to an event large or small is to whip out their phone and start recording. So what separates these everyday citizens from people who consider themselves “cop watchers?”

Cop watchers are a loose band of activists who consider it their job to police the police. They’ll show up at traffic stops or hang out in areas with a large police presence so they can document the activities of police.

You now can find cop-watching groups in dozens of cities across the country. But some officers are starting to push back, saying these groups interfere with their jobs and endanger the public.

Neena Satija, who works for Reveal and The Texas Tribune, takes us to places where tensions between cops and cop watchers have started to flare up. In Texas cities like Austin and Dallas, activists are being arrested, and police departments are asking state lawmakers to step in.