The Knox County state's attorney will now determine if new charges should be filed.
The 28-year-old Sheley is suspected of murdering six people in Illinois and two in Missouri late last month. So far, Sheley is charged in two of the murders.
Suspected killer accused of attacking inmate
GALESBURG, Ill. Nicholas Sheley is being held at the Knox County Jail in Galesburg, Illinois.
The sheriff there says Sheley unscrewed a railing from his cell and started swinging it at another inmate in the cell next door Sunday morning.
