At least six people were killed after a gunman drove around a Michigan city randomly shooting people in parking lots of an apartment complex, a car dealership and a restaurant Saturday night, authorities said.

Law enforcement sources told WMMT-TV Jason Dalton, 45, was identified as the gunman in the string of shootings. He was arrested without incident in downtown Kalamazoo following a massive manhunt.

Four people were killed outside a Cracker Barrel restaurant and a father and son were killed outside a Kia dealership, Kalamazoo County Undersheriff Paul Matyas said. A woman was shot outside an apartment complex as well. She was in serious condition as of early Sunday, Matyas said.

Matyas said earlier that authorities did not believe the shootings were targeted at specific people, describing them as "our worst case scenario."

"These are random murders," he said.

He described a terrifying rampage that began about 6 p.m. in the parking lot of the apartment complex in Richland Township on the easte edge of the Kalamazoo County, where the woman was shot and seriously wounded.

The suspect was arrested about 12:40 a.m., authorities said. Matyas told WWMT-TV that the man did not resist when approached by law enforcement officers, and that weapons were found in his vehicle.

"The threat to the public is over," Matyas said.

Michigan State Police Lt. Dale Hinz called the shooting spree “incomprehensible,” according to Fox 17 Online.

Kalamazoo, with a population of about 75,000, is about 160 miles west of Detroit. It is home to Weste Michigan University and the headquarters of popular craft beer maker Bell's Brewery. The city also is known for the anonymously funded Kalamazoo Promise program, which has paid college tuition of students who graduate from Kalamazoo Public Schools for more than a decade.

The Associated Press contributed to this report.