Chicago (CBS) — John P. Rivera, 23, has been identified as the off-duty Chicago police officer who was fatally shot in River North Saturday morning, according to the Cook County Medical Examiner’s Office.

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Rivera lived in the Hegewisch neighborhood on the Far South Side of Chicago and had been a police officer for less than two years.

One of his neighbors, John Sanchez, is a former CPD sergeant and said Rivera would ask him for advice about being a police officer.

“He was a good boy, I mean a really, really nice boy,” Sanchez said. “He ran all the time, worked out all the time with neighbor kids his own age. They’d all work out to try to be ready to be police.”

Sanchez said Rivera wanted to be a police officer since he was 16 years old and dreamed of doing tactical work.

Rivera was a 2013 graduate of Brother Rice High School. The school’s president Mark Donahue and principal Bob Alberts released a statement, saying:

“The whole Brother Rice community is mourning the loss of Officer Rivera. On behalf of Brother Rice, we express our deepest condolences to his family. John is remembered as a nice, polite, and soft spoken young man. He was always willing to help others and truly lived out our motto of ‘Acting Manfully in Christ Jesus’. God bless John and his family.”

Several people in Rivera’s neighborhood knew him as John Petty. He changed his last name to Rivera to match his mother’s.

Friends say Rivera was very kind. Neko Castillo, a longtime friend, said, “He showed me how to care about people no matter what and just how to live the best life.”

Castillo was also Rivera’s barber and shared a photo of Rivera after a recent haircut.

(Credit: Neko Castillo)

Julian Martinez also shared a recent photo of Rivera and him and one from their First Communion.

(Credit: Julian Martinez)

(Credit: Julian Martinez)

Martinez said another friend was also hit in the shooting Saturday morning but is doing well.

“He’s doing good. He was shot four times but is completely up and talking. He’s very lucky,” Martinez said.

Police confirm Rivera and three other individuals were sitting in a parked car when two men approached their vehicle near Clark and Huron Street.

One man showed a handgun and started shooting. The offenders fled the scene.

Rivera was pronounced dead at Northwestern Memorial Hospital just before 4 a.m.

First Deputy Supt. Anthony Riccio said Rivera was working 3rd watch in the 6th District and had completed a shift around 9 or 10 p.m.

Riccio said Rivera had been with the department for just under two years. Officials said one person of interest is being questioned.

Police said there were many surveillance cameras in the area where the shooting took place. Detectives are looking through footage to see if they can get video of the shooter, who remains on the run.