KALAMAZOO, Mich. - A gunman who authorities believe chose victims at random shot people in the parking lots of a western Michigan apartment complex, car dealership and restaurant, killing at least six during a nearly five-hour rampage, authorities said.

Forty-five-year-old Jason Dalton of Kalamazoo County was arrested early Sunday in downtown Kalamazoo following a massive manhunt after the shootings began early Saturday evening, said Kalamazoo Department of Public Safety Chief Jeff Hadley.

The FBI has joined the investigation into the act, and so far has not found any signs of a terror-related motive, reports CBS News senior investigative correspondent Pat Milton.

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Kalamazoo County Undersheriff Paul Matyas described a terrifying rampage that began about 6 p.m. outside the apartment complex in Richland Township on the eastern edge of the Kalamazoo County, where a woman was shot multiple times and seriously wounded.

CBS affiliate WWMT in Kalamazoo reports the suspect then fled the scene and crashed his vehicle, before fleeing on foot.

A little more than four hours later and 15 miles away, a father and son were fatally shot while looking at cars at the Seelye Ford Kia dealership. Fifteen minutes after that, five people, were gunned down in the parking lot of a Cracker Barrel restaurant along Interstate 94, Matyas said. Only one person, a 14-year-old girl, is believed to have survived that shooting.

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.

The suspect was arrested about 12:40 a.m., authorities said. The suspect was sitting in a vehicle at a traffic light that police had matched to the shootings. Matyas said 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 early Sunday.

Kalamazoo, with a population of about 75,000, is about 160 miles west of Detroit. It is home to Western 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.

"This is your worst nightmare, where you have somebody just driving around, randomly killing people," Matyas told WWMT. "There's usually a rhyme or reason to it. In this particular case, we're not finding that. Hopefully when we interview the individual he'll disclose that to us."