FOREST PARK, Ill. (AP) — A shooting on a commuter train outside Chicago on Labor Day morning left four people dead, police said.

Forest Park police Deputy Chief Christopher Chin gives a news briefing outside the CTA Forest Park station, after a shooting, Monday, Sept. 2, 2024, in Forest Park, Ill. (John J. Kim/Chicago Tribune via AP)

Three people were pronounced dead at the Forest Park station, an above-ground stop on the Chicago Transit Authority's Blue Line. The fourth victim died at a hospital.

The suspect got away but was subsequently arrested on a train on a different route, Forest Park police said.

“A weapon was recovered,” Forest Park Deputy Chief Chris Chin told reporters. "There is no immediate threat. This appears to be an isolated incident on this unfortunate day.”

Police were called around 5:30 a.m. Chin said he had no immediate information to disclose about the victims. He called the shooting “shocking” and “horrible.”

"This heinous and egregious act of violence should never have occurred, nonetheless on a public transit train," the Chicago Transit Authority, known as CTA, said.

CTA said security camera video “proved to be vital” in helping investigators.

Forest Park Mayor Rory Hoskins said his community, population 14,000, is the only Chicago suburb in Cook County where two major train lines end.

“It's a horrible tragedy that four people are dead on Labor Day weekend," Hoskins said. "Our police department and our fire department respond to this location probably more than any other location in our jurisdiction.”

A regular rider, Sean McNulty, had to take a bus Monday because of service interruptions related to the shooting. He said criminal activity sometimes is a reality on the train.

“You just kind of get used to it,” McNulty told the Chicago Tribune. "I keep my eyes open because I want to know what’s going on around me at all times.”