A man whom a Dallas police officer allegedly kicked in the head said Friday that the incident was racially motivated.
Two days ago, Lyles filed a lawsuit against the city and two officers. He and his mother spoke at a news conference at their attorney's office Friday.
"All I kept saying to them was, 'Why did you have to do me like this? I deserve none of this,'" Lyles said. "I did not deserve this.'"
Brown condemned the officer's actions but said the incident had nothing to do with racism.
But in the lawsuit, Lyles said that Williams told him while beating him, "Who's the tough one now, you fat (racial slur)."
"We need to take a real hard look at how the Dallas police are being trained and how they treat people of color in this city," the Rev. Ronald Wright of Justice Seekers said.
Police released dashboard camera video of the incident, but the footage does not have sound.
Lyles also said in the lawsuit that Williams and another officer laughed while they took him to jail, drove fast and deliberately slammed on the brakes so that he was tossed around "like a sack of groceries."
"They kept him on the ground for I don't know how many minutes," Ella Flowers, Lyles' mother. "They talked bad to him. They did him like a dog. So I want to know, how would you feel if they done your son like that?"
Dallas police said Williams became angry when Lyles fell on his arm during a scuffle after he resisted arrest. Police said Williams punched Lyles and hit him with a flashlight until another officer took the flashlight.
"They got down on the ground, and they beat him in the head with an aluminum flashlight," Flower said. "But that wasn't good enough. They punched him in the eye. Then they tased him."
Lyles said he was not resisting arrest on a traffic warrant. He said that he had trouble putting his hands behind his back because he is overweight and told officers they would need two sets of handcuffs.
On dash-cam video released by Dallas police, Williams can be seen spraying pepper spray into Lyles' face and kicking him in the head while he was handcuffed and lying facedown on the ground.
"My son was illegally beaten like a dog or a piece of paper on the ground," Flowers said.
Williams faces a charge of official oppression, a misdemeanor.
NBC DFW's Scott Gordon contributed to this report.