A New York City jail captain and a correction officer have been charged with assault and other crimes in the beating of a mentally challenged 18-year-old inmate at Rikers Island.

Capt. Medzid Kolenovic (kohl-ih-NOH'-vihk) and Officer Jean Destine (jahn dehs-TEEN') pleaded not guilty Friday to misdemeanor assault and to felony charges that they altered use-of-force documents.

Prosecutors say Kolenovic and Destine beat the inmate in a supply closet after an argument. They say the two also falsely claimed workers' compensation after the Dec. 9 beating of Ambirorix Celedonio (am-beer-OHR'-ee sehl-ih-DOH'-nee-oh).

Officials say the two guards are being suspended. Their lawyers didn't immediately return messages seeking comment.

Celedonio's attorney says he has an IQ of 65. He was being held on a gang assault charge, but he's no longer in custody and his case has been sealed.