Officers arrived at 8:05 a.m. Monday at the intersection of Howard and 22nd streets after someone called police.
They found the body of a 24-year-old man in the driver's seat of a gray Kia Sorrento.
The man appeared to have been shot to death.
His body was taken to the Delaware County Medical Examiner's Office, where an autopsy will be performed.
Anyone with information about the case was being asked to call the Chester Police Department Detective Division at 610-447-7908, Capt. James Chubb at 610-447-8433 or the Delaware County Criminal Investigations Division at 610-891-7700.