Guards closed all ten divisions of the jail complex overnight as a precaution after they learned that someone snuck in a weapon to the complex. The lockdown is slowly being lifted.
The focus of the search appeared to be Division 10, a maximum-security section of the jail. Guards were going cell to cell searching for the weapon. Division 10 will remain on lockdown.
Officers questioned inmates, visitors and other workers at the jail.
Cook County sheriff's investigators are trying to find out how the gun may have gotten into the jail. Everyone entering the facility must pass through metal detectors, be patted down and searched before they enter.