A chilling video of Maryland police silencing an innocent student who was recording the arrests of two other people has civil libertarians outraged.

The arrests were made at night on the streets of Towson, Maryland. A University of Maryland-Baltimore County student who witnessed the arrests decided to record them using his cell phone. The student, 21-year-old Sergio Gutierrez, was soon approached by officers who objected — wrongly — to his actions.

Gutierrez repeatedly told the officers that he knew he had the right to film them, but the cops were prepared to use any excuse to shut him down. First they told him that he was hampering their investigation, even though he was standing well enough away while the arrests were being made.

Still, the student maintained that he was in the right.

“I am allowed to film,” said Gutierrez.

The cops told him that he was diverting their attention and that he had to leave. When Gutierrez persisted, they told him that he would be arrested if he did not stop recording.

“I thought I had freedom of speech here,” he said.

The cop’s answer? “You don’t. You just lost it. Walk away and keep your mouth shut.”

Police shoved Gutierrez, told him to “shut your fucking mouth,” and eventually forced him to leave the area.

Many of the people who watched the video were disturbed by the officers’ behavior. So too was the Baltimore County police department, which has launched an investigation, according to WBALTV-11.

Gutierrez told local news that he was glad he recorded the incident. Police may have acted even worse if they knew the camera was off, he said.