A watchful Thorntons' customer was fatally shot by masked armed robbers moments after warning the clerk when he spotted them outside the station early Tuesday in the Brighton Park neighborhood on the city's Southwest Side. The attack unfolded just before 3 a.m. Tuesday when a white Hyundai with four men inside pulled into the parking lot and circled the station at 3450 S. California Ave., according to a police report obtained by the Chicago Sun-Times. As one of the assailants got out and asked the clerk if he could use the washroom, the 36-year-old Willowbrook man, who had just parked next to them, entered the station to buy coffee and gas, and he alerted the clerk there were "guys with masks in the lot," according to the report and sources. The clerk told the 36-year-old man she'd lock the door after he left, but as he was trying to leave, the other three assailants jumped out of the car and shot the man in his head, neck and chest before robbing the station of cash from one of the drawers, the report said. The victim, who may have returned fire, was dead on the scene, according to the Cook County medical examiner's office and police. Before the four robbers drove off they took something that was lying next to the 36-year-old man, who had an empty holster, according to the report. His name has not been released. Ten 9-mm casings were found in two locations at the scene and suspected blood was also present, according to the police report. Area 1 detectives are investigating. ...read more read less