A video showing police in Madison, Wisconsin, violently assaulting an unarmed black teenage girl at a mall has gone viral, and the footage captured by a bystander is causing alarm as it spreads across social media.

In the video, originally posted by Facebook user RichBoy Robinson, the girl, who local media identified as 18-year-old Genele H. Laird, is seen standing in front of the East Towne Mall on East Washington in Madison, Wisconsin, being manhandled by a police officer. The officer, who is struggling with the girl to force her to the ground, soon gets help from a backup officer, who proceeds to repeatedly drive his knee into Laird’s ribs. The officer also punches Laird several times.

After Laird is beaten into submission, the two officers hold her on the ground, while one repeatedly uses his taser on Laird’s torso and leg. During the beating, Laird is heard screaming and pleading with the police to get off of her, saying “I can’t breathe.” Near the end of the video, a bag is put over Laird’s head while she lies facedown on the concrete.

TRIGGER WARNING: This video is extremely violent and upsetting.

In a press release, the Madison Police Department alleged that before the girl was taken outside the mall, she had threatened an employee at a Taco Bell restaurant in the mall’s food court, accused a worker of stealing her phone, and allegedly brandished a knife. However, Laird appears unarmed in the video circulating on social media.

According to Channel 3000 in Madison, Laird was arrested on tentative charges of disorderly conduct while armed with a knife, resisting police causing injury, battery to a police officer, and discharge of bodily fluid.

A shorter video showing the beating and tasing was posted by RichBoy Robinson at 7:20 p.m. local time, and has already been viewed over 300,000 times as of this writing. Watch it below:

Neither Robinson nor the Madison Police Department immediately responded to interview requests.