Four people killed as they slept on Chicago subway train in mass shooting

Police have arrested one person in connection with the shooting

Police tape blocks off the Forest Park Blue Line train station. Four people were killed on a Blue Line train at the Forest Park station early Monday morning (AP)

Four people were killed in a shooting on Chicago’s Blue Line train early Monday morning.

The shooting happened around 5am local time in Forest Park, Illinois, ten miles outside of Chicago, ABC 7 reported. Three people were pronounced dead at the scene, while the fourth victim was transported to a nearby hospital where they later died.

The victims, who have not been publicly identified, appeared to sleeping at the time of the shootings, the Forest Park Police Department told CNN, and may have been homeless.

“We don’t know for sure what their social status is. Looking at the videos, they were asleep on the train,” Forest Park Deputy Chief Chris Chin told the network.

Police later arrested the suspected shooter on a Pink Line train in Chicago after they fled the scene, according to ABC 7. Officers recovered a gun during the arrest.

“Although this was an isolated incident, this heinous and egregious act of violence should never have occurred, nonetheless on a public transit train,” the Chicago Transit Authority said in a statement.

“As soon as this matter was reported, CTA immediately deployed resources to assist the Forest Park Police in their investigation into the matter, including review of all possible security camera footage, which proved to be vital in aiding local enforcement,” the statement continued.

Police cars sit outside the Forest Park station. Officers have arrested the suspected gunman who killed four people on a Chicago Transit Authority Blue Line train early Monday (AP)

The investigation has since been turned over to the Forest Park police and the West Suburban Major Crimes Task Force. Officials say this was an isolated incident and there is no longer a threat to riders, according to ABC 7.

“We commend both the Forest Park Police Department for their thorough and collaborative efforts to provide information to partner agencies; as well as the Chicago Police Department whose quick actions led to the apprehension of a suspect in this matter,” the CTA said.

Forest Park Mayor Rory Hoskins called the shooting “an outlier” in a statement on Monday.

“To the extent that our leaders in Springfield are considering any kind of CTA-mass transit reorganization, we would ask them to consider investing additional resources in terms of safety, public safety, law enforcement personnel, what have you, to support a small community like Forest Park that has to respond to two major train lines ending in Forest Park,” Hoskins said.

This incident comes one week after the CTA implemented a new program, powered by artificial intelligence, that can automatically detect when a rider has pulled out a gun, the Chicago Tribune reports.