Cook County Jail was put on lockdown after an officer found a handgun in a trash can, officials said.
According to Kara Smith, a spokesperson for the Cook County Sheriff's office, an officer was emptying a trash can in the "receiving" area when a Cal Tech handgun was found. The area is a location where police departments drop off prisoners to be processed by the sheriff's office for bond court.
Smith said the weapon was small enough to fit in the palm of a hand.
The jail was placed on lockdown so each division could be search, but authorities said they had no reason to believe other weapons were inside.
Smith said they believe the gun was brought in by someone recently arrested and that person tossed the gun. It was not clear who the weapon belonged to.
The jail remained on lockdown after 1 p.m.