Four people were killed in a shooting on a Chicago Transit Authority train early Monday.

The Forest Park Police Department got a 911 call around 5:27 a.m. about victims with gunshot wounds on a train at the Blue Line station at 711 Desplaines Avenue, Forest Park, it said on Facebook.

Police found four people with gunshot wounds, they said. Three were pronounced dead at the scene, and the fourth died at Loyola University Medical Center.

Law enforcement did not identify any of the victims pending notification of next of kin.

The suspect was found on a Pink Line train through security video and arrested, police said, adding that the shooting appears to be an isolated incident and poses no immediate threat to the community. Only one suspect is believed to have been involved in the shooting, which was targeted, officials said at a news briefing Monday afternoon.