Trans man's violent arrest under investigation by Los Angeles sheriff's department

The Los Angeles County Sheriff's Department said it's investigating a transgender man's violent arrest after he and his lawyer released surveillance footage of the February encounter.

Emmett Brock, 23, told ABC News that he was beaten by a Los Angeles County Sheriff's deputy after he gave the middle finger to the officer who Brock alleges was behaving harshly toward a woman on the side of the road. Surveillance footage of the arrest was obtained by Brock's attorney from a nearby store and released to ABC News.

"The Los Angeles County Sheriff's Department takes all use of force incidents seriously," the department said in a statement Tuesday.

The statement added, "The Department is investigating the information and allegations brought forward by Mr. Brock and his attorney. Unfortunately, we cannot comment any further at this time due to the pending litigation in this matter."

Brock said the incident began when he was driving and observed the deputy "just acting in a very domineering, abusive way towards this woman on the street."

After making the gesture to the deputy, Brock said the same deputy hopped in his car and began following him. Brock said he proceeded to deviate from his route to see if the deputy would keep following him.

Brock said he called 911 and claims he was told "If he doesn't have lights or sirens on, he's not pulling you over. If he hasn't pulled you over, he hasn't pulled you over. Continue to your destination."

Brock pulled into a 7-Eleven parking lot when the deputy's car pulled in behind him and turned his lights on before Brock got out of the car, which can also be seen in the surveillance footage.

As Brock got out of his car, the deputy can be seen in the footage approaching Brock, grabbing him and throwing him to the ground.

"He's on top of me very quickly," Brock told ABC News. "I took a step and then immediately was just grabbed, thrown on my head. He punched me, I think, about 10 times with a closed fist on both sides of my head -- just beating me and I was bleeding from my ears, and my face was hugely swollen."

The deputy can be seen in the video hitting Brock while the two were on the ground.

He alleges that officers told him he was arrested for resisting but would not tell him why exactly he was approached by police in the first place.

The deputy has been identified in local news reports as Joseph Benza. Benza's attorney Tom Yu told ABC-owned station KABC that his client was trying to take control of the situation when Brock apparently tried to walk away from the traffic stop.

"A traffic stop is inherently dangerous," Yu told KABC. "It evolves very fast, very rapidly. You don't know if a person is armed. So my client immediately took control of that situation in an attempt to stop Mr. Brock from walking away from that traffic stop."

Brock says when he revealed in a local jail he is transgender deputies began asking "invasive" questions about his gender identity and genitalia and allegedly made him expose himself to a female officer inside a restroom, after which he says he was placed in a women's holding cell.

Brock has been charged with two misdemeanor charges, including battery against a police officer and resisting arrest. Brock has pleaded not guilty to the charges.

He said he is pursuing legal action against the Los Angeles County Sheriff's Department.

The sheriff's department did not release the arresting officer's name to ABC News.