AUSTIN, Texas — A video of a man being arrested by Austin police officers has now gone viral.

In the video, a man is being held down on the ground by two officers and at one point one of the officers repeatedly punches the man. A woman is also heard screaming in the background as officers as her repeatedly tell her to back up.

The video was posted by a Twitter user named Patty and tagged the Austin Police Department.

Austin Police Department Chief Brian Manley on Thursday addressed the arrest during a press conference at police headquarters. Manley said the video of the incident starts at about the halfway point of the officer interaction. Manley said the suspect, identified as Justin Grant, grabbed a Taser from an officer. That Taser was deployed, Manley said, because Grant reached for a six-inch knife. 

Manley further said police policy allows an officer to punch a suspect in the head in the event of an imminent safety threat, which was present in this case. Manley urged anyone who witnessed the arrest and the events leading up to it to contact the department. He said the body cameras worn by both officers stopped working during the struggle. 

As of Wednesday the video has more than 78,000 views.

According to an affidavit, police were originally called to Rain Nightclub for a disturbance call at 1:30 a.m. July 4. Grant was denied entry at the nightclub. When he was asked to leave by an employee, Grant pulled him close to his face and told him to let him into the bar or “something bad would happen.” The employee then observed Grant motion his hand towards his waistband and observed a knife. The employee then called police.

The affidavit identifies the officers as Officer Hale and Officer Alas. When they arrived, witnesses pointed Grant out to offers as the man who was denied entry.

When officers tried to detain Grant, police said he immediately tensed up his arms and resisted detainment. Officers commanded Grant to stop resisting but he did not comply. Officers were then able to get Grant to the ground. Eventually police said they were able to detain Grant after approximately a minute.

The affidavit does not mention one of the officers punching Grant.

Police said they located a knife in his waistband and a small bag that tested positive as methamphetamine.

Grant was arrested on charges of terroristic threat and possession of a controlled substance.