CHICAGO (AP) — Chicago police say a man is dead after an early-morning shooting on a city train platform.

Authorities say a 33-year-old man was arguing with another person on the Chicago Transit Authority platform around 2:40 a.m. Monday at a Red Line stop on the city’s South Side. Police allege the second person pulled out a handgun and shot the 33-year-old in the head and chest. He was pronounced dead at a hospital.

Witnesses told police they heard five or six shots.

Police are investigating. No one is in custody in connection with the shooting.

Trains temporarily bypassed the Garfield station after the shooting. Normal service resumed before 5 a.m.