The man, Edward Thomas, 29, was arrested late Sunday and charged with aggravated assault with serious bodily injury, the Dallas Police Department said.
At a news conference Monday, Lt. Vincent Weddington said that the episode, which took place following an automobile accident in the parking lot of an apartment complex, was being investigated as a possible hate crime and that more arrests were likely.
A video of the episode showed a man later identified by authorities as Thomas repeatedly punching a woman on the ground as she struggled. Other men in the crowd kicked her, before a group of women helped her get away.
The video “shocks the conscience,” Weddington said. “This is being taken very seriously in our department.”
Before approaching the woman, a voice on the video is heard telling Thomas that he would receive $200 to beat her up and that “the money was in his pocket,” according to a police affidavit for an arrest warrant.
Police said the victim, who uses the name Muhlaysia Booker, was hospitalized after suffering a concussion and a fractured wrist in the beating.
The episode began Friday afternoon, when Booker, who was driving a black SUV, backed into a car in the parking lot, according to the affidavit. The car’s driver said he tried to run her SUV off the road and pulled a gun on Booker after she tried to flee.
Thomas was part of a large crowd that had gathered in the parking lot, according to the affidavit. The video, according to police, shows Thomas’ shadow pulling on gloves before hitting Booker with his fists.
According to police, people in the crowd shouted homophobic slurs during the beating.
On Sunday night, Thomas flagged down an officer at a gas station about an unrelated matter. The officer later recognized Thomas from the video, leading to his arrest.
Thomas admitted to the beating, but denied saying anything “derogatory,” according to the affidavit.
On Monday, Thomas was ordered held in jail with bail set at $75,000. It was not immediately clear whether he had a lawyer.
Attacks on transgender people have been rising, according to advocacy groups. At least 26 transgender people were killed in the United States last year, most of them black transgender women, according to the Human Rights Campaign, an advocacy group.
In 2017, that number was 29, the most ever recorded, the group said.
Mayor Mike Rawlings of Dallas said in a statement after the attack that he was “extremely angry about what appears to be mob violence against this woman.”
"Those who did this do not represent how Dallasites feel about our thriving LGBTQ community,” he said. “We will not stand for this kind of behavior.”
This article originally appeared in The New York Times.