The judge said he was in “a lot of pain” and went with Mr. Rashid to the emergency room at Elmhurst Hospital Center, where a doctor examined his throat by snaking a tube with a camera on the end through his nose and down his throat to determine whether his trachea had been damaged. The doctor, he said, found no damage; Justice Raffaele was released and told to see his personal doctor for follow-up care.

When they first came upon the crowd, the judge said, he was immediately concerned for the officers and called 911. After he made the call, he said, he saw that one of the officers — the one who he said later attacked him — was repeatedly dropping his knee into the handcuffed man’s back.

His actions, the judge said, were inflaming the crowd, some of whom had been drinking. But among others who loudly expressed their concern, he said, was a woman who identified herself as a registered nurse; she was calling to the officer, warning that he could seriously hurt the unidentified man, who an official later said was not charged.

Justice Raffaele said that after the officer struck him and he regained his composure, he asked another officer who was in charge and was directed to a sergeant, who, like the officer who hit him, was from the 115th Precinct. He told the sergeant that he wanted to make a complaint.

The sergeant, he said, stepped away and spoke briefly with some other officers — several of whom the judge said had witnessed their colleague strike him — and returned to tell the judge that none of them knew whom he was talking about. As the sergeant spoke to the other officers, the judge said, the officer who hit him was walking away.

At the hospital, he said, he saw another sergeant from the 115th Precinct, who took his complaint. He also telephoned the Police Department’s Internal Affairs Bureau. He said he was interviewed on Friday by a lieutenant and a sergeant from a special unit in the bureau called Group 54, which investigates complaints of excessive force.

Deputy Commissioner Paul J. Browne, the Police Department’s chief spokesman, said in an e-mail that all force complaints, whether they involve serious injuries or not, are referred to the Civilian Complaint Review Board, an independent agency that investigates allegations of police misconduct that does not rise to the level of a crime. The department’s Internal Affairs Bureau investigates complaints of excessive force that involve serious injuries.