CHICAGO (CBS) — Chicago Police Capt. Thomas McMahon is retiring on Monday, but that didn’t stop him from putting his life on the line to chase a killer on Friday.

McMahon is retiring Monday after 37 years on the force. He was off duty in Roseland Friday when he heard gunfire. He chased the assailant who fired shots at the captain during the incident on the Far South Side.

“He was off duty. He heard shots and he saw them. They started running from the scene and he followed them,’’ Calumet District police Capt. James O’Donnell said.

The attack occurred about noon when Cordaro Nash, 20, was shot at East 111th Street and South Vernon Avenue, police said.

“He saw this go on and he took action. That’s what we do,” O’Donnell said.

O’Donnell said the assailants fled in a van and as McMahon gave chase and the suspects fired at him. He was not hit, but his vehicle was struck by gunshots.

“At some point they leaned out and fired shots at him. He still followed them,” according to O’Donnell, who said McMahon did not return fire.

The suspects started driving down a one-wary street then doubled back and got away through an alley.

“He did an outstanding job,” O’Donnell said.

Nash, of 12918 S. Eggleston Ave., was pronounced dead at 12:35 p.m. at Advocate Christ Medical Center in Oak Lawn, according to the Cook County Medical Examiner’s office. An autopsy Saturday determined Nash died of multiple gunshot wounds and his death was declared a homicide.
O’Donnell said McMahon, who is also assigned to the Calumet District, is scheduled to officially retire Monday.

Calumet Area detectives are investigating.

The Sun-Times Media Wire contributed to this report.