Jahmel Leach, 16, suffered facial fractures and jaw damage, according to lawyer Mark Shirian.
The New York Police Department did not immediately answer questions about Leach’s arrest, saying the issue was under internal review.
A source familiar with the investigation told CNN that a 16-year-old boy was arrested in the Bronx on June 1, after police saw the person pouring unknown liquid into a pile of garbage in the middle of the road and lit it on fire.
According to his lawyer, Leach was walking home at the time, and was not part of the protest or riots. Leach denies the charges against him and has not been charged, Shirian told CNN.
“They have no reason to arrest him,” Shirian said. “Are we going to allow them to supervise young people like that?”
The Leach family gave a press conference on Thursday, with supporters wearing shirts that said “Justice for Jahmel Leach.” The Leach family alleged that he was released for his parents to dress only partially, in a hospital gown.
“I demand justice, and I will not stop until I get it,” Leach’s mother Daisy Acevedo said during a press conference.
Mayor Bill de Blasio called for an internal police investigation to be completed with “speed and transparency.”
“I want to make sure we get the truth, and I want to make sure we follow up based on what the facts tell us,” De Blasio said on Thursday.