The video shows the officer viciously knee the defenseless 24-year-old in the face.
A group of Texas friends filmed themselves being violently arrested for "cussing in public".
The incident occurred in Baytown on Tuesday when childhood pals Skylar Gilmore, Isaiah Benavides and Isaiah Phillips pulled into a gas station to film a traffic stop of a fourth friend, Jostin Moore, who was in a separate car.
The trio watch and continue to record from a distance as the officers place Moore — who is black — in handcuffs, while they question what it is he did wrong.
But four minutes into the video, one of the officers, Nathaniel Brown, suddenly marches across the forecourt and grabs Gilmore by the wrist.
"You're cussing in public," he accuses. "Put your hands behind your back."
Wrenching the 24-year-old's arm behind his back, he slams him up against the wall, then throws him aggressively to the ground; while he's sitting defenseless on the ground, Brown then viciously knees him in the face.
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Lying facedown on the ground, Gilmore holds his own hands behind his back waiting to be cuffed.
Benavides even asks permission of the officers to move closer to film, while Gilmore begs his friend to keep the camera trained on him.
"Keep up with that mouth, you're going to go down," the officer warns the others.
"It's illegal to talk? It's freedom of speech bro," they retort.
"Not that speech. That's disorderly conduct," the cop warns, before they suddenly grab Phillips and slam him face-down into the hood of a car.
Ironically, Brown then swears at Benavides, pointing into his camera as he warns: "If you don't get back I'm gonna break your shit."
He then returns to Gilmore and tries to drag him to his feet, who roars in pain trying to tell Brown he suffers from car crash injuries.
"He has a messed up hip! He got into a car crash - he literally has stitches going down his leg," Benavides pleads.
According to KHOU, Baytown police later confirmed both Gilmore and Phillips were arrested for disorderly conduct-language for using profanity.
A spokesperson for Harris County District Attorney's Office said prosecutors dropped a separate charge of "interfering with public duties" against Gimore because of lack of evidence.
Moore meanwhile, police said, was arrested on unspecified traffic violations and an "outstanding warrant" out of Deer Park — even though neither officer appears to run his details during the traffic stop.
"They slammed me on my friend Skylar’s hood, used my face to dent his hood," Phillips told the site. "That's not proper."
"This was my first time going to jail," Gilmore added. "I'm a law-abiding citizen, and I got sent to jail for cursing."
"It got crazy too fast," Benavides told TooFab on Friday. "I did what I could I tried to calm everything down.... I stayed quiet and only tried to be peaceful, and he still threatens me."
"I was concerned for us and I'm still concerned with what's going on because I don't want anyone else too be in our situation and be scared to stand up... We stood up and we will keep going."
Baytown Police Chief Keith Dougherty himself filed a complaint against the officers, and ordered an investigation.
"I try to hold people accountable, and I feel the frustration," he said. "Obviously I felt that there were some better judgments that could have been made, and so that's why I called for the investigation."
They've both been restricted to desk duty during the investigation, which could result in their termination.
Brown was previously accused of siccing a K-9 on a black man, who was on the ground with his hands behind his back, after he fled a traffic stop on foot after allegedly failing to signal.
Body cam footage of that incident was subsequently released, showing the victim Raphael White screaming in agony as the dog savages his arm.
On Thursday Benavides, Phillips and Gilmore joined hundreds gathered outside Baytown Police Station to protest the death of Pamela Turner, who was shot dead by a different officer from the department in March of last year; this latest incident with the group of friends just added to the anger.
A petition for Brown's termination from the force has since been set up on Change.org.