CHICAGO (CBS) — Police are investigating the death of a man whose body was found on a set of subway tracks along the Blue Line near the LaSalle Street station overnight.

Police News Affairs Officer Robert Perez said a conductor told police he was pulling into the LaSalle Street subway station, at 150 W. Congress Pkwy, when he noticed what looked like a duffel bag in a restricted area of the platform around 1:45 a.m. Monday.

The conductor stopped the train and got out to inspect the bag. It was then, according to police, that the conductor noticed the “mangled body of an individual” on the tracks who had apparently been hit by another train.

Service resumed on the Blue Line at 4:10 a.m..

The Cook County Medical Examiner’s Office is not yet releasing information about the identity of the person who was killed.