The prosecutor said Sergeant Webb admitted to the shooting and told officers who took him into custody where he had put his guns — a .40-caliber Glock and .380-caliber Glock. Mr. Hanley said they were recovered from behind Sergeant Webb’s bag, but that neither was military-issued.
Three men were killed. They were identified by the Winnebago County Coroner’s Office on Monday as Thomas Furseth, 65, of Machesney Park, Ill.; and Jerome Woodfork, 69, and Dennis Steinhoff, 73, both from Rockford, a city of nearly 150,000 people about 90 miles northwest of Chicago.
Two victims remained in critical condition, Mr. Hanley said: a 14-year-old boy who was shot in the face and a 65-year-old man who had multiple gunshot wounds. A 16-year-old girl who was shot in the shoulder was treated at a hospital and later released.
“We believe this is a completely random act,” Dan O’Shea, the Rockford police chief, said at a news conference on Sunday. He said there was no known association between the gunman and the victims.
Regina Maschke, whose father was Mr. Steinhoff, was at home when she got a text from her niece telling her about the shooting. Her father had been to her house for dinner and left shortly after 5 p.m. to meet his friends at Shooters, the bar above the bowling alley, where she said her father was a regular.
“He felt safe there,” Ms. Maschke said, adding that Mr. Steinhoff went several times a week to watch horse races and to socialize. “That was his home away from home.”
Mr. Steinhoff was a Vietnam War veteran who worked for years as a union committee man for Chrysler, until he retired at 55. He loved sports, especially basketball, and before the coronavirus pandemic, frequently traveled to referee games.