Six people were killed and about 24 others were seriously hurt in the shooting, according to officials.
Police said they apprehended Robert “Bobby” Crimo III following a vehicular pursuit Monday evening after an hours-long manhunt.
It appears the gunman fired from a roof where a high-powered rifle was recovered, police said.
Police are describing the shooting as a “random act of violence.”
Shortly after the police released a photo of Crimo and his car, officers said a North Chicago police unit they spotted the person of interest in a vehicle matching the one they were looking for.
After a traffic stop, the driver fled and led police on a brief pursuit, authorities said. He was stopped at U.S. Highway 41 and Westleigh Road in Lake Forest, Illinois, where he surrendered, according to police.
Ryan Lerman, a delivery driver, was near the intersection and filmed the arrest as it took place. He told Chicago ABC station WLS that he immediately recognized the car from the police bulletins.
“Right away he was surrounded by the police,” he told the station. “They came from either side of the highway to surround him.”
The video showed armed officers approaching the car with their guns drawn and ordering the driver to get out. The driver was seen putting his hands in the air.
“It ended with him getting on his knees and getting arrested by cops,” Lerman said. “It was surreal, I didn’t know what I was seeing.”
The arrest capped a frantic day that began with a popular parade in the neighborhood.
The parade was about three-quarters of the way through when the shooting broke out, authorities said. Revelers fled in panic, leaving behind empty strollers, overturned chairs and half-eaten sandwiches.
Five people — all adults — died at the scene and a sixth victim died at a hospital, said Lake County Coroner Jennifer Banek.
One victim has been identified by family members as 78-year-old Nicolas Toledo. His family told ABC News that Toledo moved to the U.S. from Morelos, Mexico, in the 1980s.
A Mexican national is also among the deceased, according to the Ministry of Foreign Affairs of Mexico.
The NorthShore University Health System said it has a total of 31 patients; most suffered gunshot wounds and a few were hurt in the chaos. At least one child is critically injured, Highland Park Fire Chief Joe Schrage said.
When the gunfire erupted, parade-goer Zoe Nicole Pawelczak grabbed her dad and started running through the sea of people.
“I saw multiple people slaughtered,” she told ABC New