Soldier charged with murder after three dead in US shooting
A further three people were injured when a man opened fire in Rockford's Don Carter Lanes bowling alley on Saturday night.
The highly decorated Green Beret was assigned to the US Army's 7th Special Forces Group, based in Florida, and had served four Afghan tours.
Hanley named those killed as Thomas Furseth, 65, from Machesney Park in Illinois, Jerome Woodford, 69, and Dennis Steinhoff, 73, who were both from Rockford.
Of those wounded, the state attorney said a 16-year-old girl was stable, while another teen -- a 14-year-old boy -- and a 62-year-old man remain in a critical condition in hospital.
"The defendant admitted to the shootings, and directed officers to the locations of the firearms he used," Hanley told the press conference.
Two weapons were recovered at the scene.
Webb was on leave and reportedly visiting family at the time of the attack.
He is due to appear again in court on February 16, and could face life imprisonment without parole if convicted.
A decorated Special Forces assistant operations and intelligence sergeant, Webb finished his most recent tour of Afghanistan in July, US media said.
Media reported his lawyer saying Webb might have PTSD (post-traumatic stress disorder) although noting he will need a medical examination before that can be confirmed.
Major General John Brennan, commander of 1st Special Forces Command (Airborne), said Webb's actions were "abhorrent and are absolutely not representative of the Special Forces Regiment."
"The actions described in reports are shocking and are completely out of character with Webb's 12 years of honorable service," Brennan told the New York Times.