Chicago deputies have released video that shows the accused killer of an 11-year-old girl being pummeled by another pre-trial detainee in a courthouse lockup.

THE WEEK IN PICTURES

Reputed gang member Antwan Jones, 19, was attacked Wednesday as he was dozing in a chair at the Leighton Criminal Courthouse before a bond hearing, the Chicago Sun-Times reports.

The video released Thursday by the Cook County Sheriff's Office shows a man in prison garb striking Jones several times in the head with his fists. Jones was cuffed to the chair at the time. A guard grabbed the assailant.

SHOOTING THAT KILLED CHICAGO TODDLER CAPTURED ON VIDEO

Deputies identified him as Renard Williams, 24, who was behind bars on a murder rap himself, the paper reported.

There was no explanation for the attack. Deputies say Williams has been cited for the attack. He’s also been disciplined for other infractions behind bars, including indecent exposure, according to the paper.

Jones has been charged with murder in the death of Takiya Holmes over the weekend.

Prosecutors say she was killed when Jones opened fire at rivals selling marijuana on his gang’s turf, the Sun-Times reported.

Jones turned himself in after witnesses identified him as the shooter.