Eric Dewayne Rawls was held Monday on a manslaughter charge in the October death of Danny Kleinbak. Kleinbak was watching television in a closed behavioral observation area when he allegedly was punched in the head.
The Dallas Morning News reported Sunday that the men were not supposed to be in the same area.
The sheriff's department declined comment on the incident, but says officials strive for continuous improvements in operations.
Bond was $100,000 for Rawls, who originally was held on a charge of injury to a child. His attorney did not immediately comment Monday.
Records show Kleinbak had a criminal history of misdemeanors. His attorney blames negligence for his death.