A Cook County Sheriff's spokeswoman says Illinois inmates involved in a shooting inside the county jail last week may have staged the incident in hopes of suing the county.

Sally Daly said yesterday that one of the inmates has told investigators about the plan to sue the county for failing to protect the inmates by allowing a handgun into the prison. Three inmates -- Gregory Sherman, Terry Martin and Lorenzo Evans -- all sustained minor injuries in the February First shooting.

Daly said authorities have identified a fourth inmate believed to be the gunman, but no charges have been filed. Prosecutors earlier this week charged a 21-year-old woman with smuggling the gun into the jail and slipping it through a plexi-glass divider.