Mr. Jackson said that Officer McKie was a husband and father of two who spent two years at the University of Buffalo on a basketball scholarship.

The lawyer added that the officer had an exemplary record in his five years as a correction officer.

“My client would have no motivation whatsoever to engage in this behavior,” he said, adding that the prosecution’s case was “predicated upon inmates who now, in an effort to save themselves, are pointing fingers.”

Renée C. Hill, Officer Nelson’s lawyer, said her client “denies the charges adamantly.”

The third correction officer who was indicted, Denise Albright, 43, of Manhattan, was not present when Mr. Robinson was killed, according to Mr. Jackson, who also represents her. She was charged with several crimes, including assault and conspiracy, and faces up to 15 years in prison if convicted.

Officer Albright pleaded not guilty and was held Thursday in $50,000 bail. Twelve inmates were also indicted in connection with the criminal ring and were expected to be arraigned Friday.

Three of them, Joseph Hutchinson, Anquant Bryant and Shaddon Beswick, all 18, were charged with first-degree manslaughter in the death of Mr. Robinson.

Outside the courtroom, Mr. Robinson’s mother, Charnel Robinson, held up a photo of her and her son embracing. Tears rolled down her cheeks.