CHICAGO (CBS) — An off-duty Chicago police officer shot three people during an altercation overnight at a bowling alley in south suburban Blue Island.

Blue Island Police said, around 11:45 p.m. Tuesday, officers responded to a shooting at Burr Oak Bowl at 3030 W. 127th St.

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When officers arrived, they found three people who had been shot. Two of them were taken to Advocate Christ Medical Center, where one of them remained hospitalized Wednesday afternoon with a gunshot wound to the chest. The third victim drove himself to a local hospital for a superficial graze wound.

Multiple police sources told CBS 2’s Suzanne Le Mignot the incident began as a domestic dispute between the officer and his girlfriend, inside a bathroom at the bowling alley.  Two men tried to help her, and sources said that’s when the off-duty officer fired his gun, shooting one man in his hand and the other in his shoulder as they tried to intervene. A third man also was shot.

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After the shooting, sources said the off-duty officer fled the scene, and while driving, he threw the weapon out of his car window. Police have recovered that gun. It was not clear if the gun is the officer’s service weapon.

Blue Island Police said two people were taken into custody after the shooting, including the off-duty Chicago police officer.

The officer is assigned to the 5th (Calumet) District, at 727 E. 111th St., and is still in his 18-month probationary period as a new officer. Chicago Police said he has been relieved of his police powers as part of the investigation into the shooting. CBS 2 has also learned, before working for CPD, the officer was employed as a court liaison at Cook County Adult probation.

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The Civilian Office of Police Accountability, the Chicago agency tasked with investigating shootings by CPD officers, is working with the Blue Island Police Department to investigate the shooting.

Suzanne Le Mignot