Former supervisor remembers Chicago police officer John Rivera killed in River North in emotional Facebook post

CHICAGO (WLS) -- A former supervisor of the Chicago police officer fatally shot over the weekend called him "the future of policing."

Police Sgt. Melissa Malm was, until a few months ago, John Rivera's supervisor on District 6's third watch. Rivera, 23, was fatally shot early Saturday while he sat in his vehicle in the River North neighborhood after a night out with friends.

RELATED: Off-duty Chicago cop killed in River North shooting identified

John Rivera, 23, was a Chicago cop for almost 2 years. He was off-duty when fatally shot after a night out with friends in the River North neighborhood.

"He was the future. He was supposed to be at least," Malm said in a Facebook post written a day after the shooting.

"Knowing who he was. Knowing that he protected someone else's life when he passed speaks volumes. And that's him. Giving his life to protect people in the car. That's Petty," Malm said.

"Petty" was the name that his friends and family knew him by. Born John Petty, it was his name until just recently, when he became John Petty Rivera.

"He says the streets just didn't agree with my name, Sarg. And it all made sense to me, I knew what he meant because he was challenged by his name. When you get called Petty on the street, it's an insult," she said. "This was serious to him. He really valued his reputation as a police officer. And that spoke volumes."

RELATED: 2 charged in fatal shooting of Officer John Rivera

Two men have been charged in the fatal shooting of off-duty Chicago Police Officer John Rivera.

Rivera was serious about career, but also a jokester. Goofy even.

In a photo, Rivera is shown with a hot dog bun in his shirt pocket is, Malm said. It was just one example of why people enjoyed being around him.

Who he was in his totality, is why she chose to write that emotional Facebook post.

"I didn't want him to become just another statistic of Chicago gun violence. I thought the city deserved to know what they really lost. They lost a great human being. And a great human being who was working to make the city better," Malm said.

Police continue to search for a third person believed to be involved in his killing.

WATCH: Supt. Johnson discusses charges in shooting of Officer Rivera

Superintendent Eddie Johnson speaks after two men were charged int he shooting of an off-duty Chicago police officer.

FUNERAL ARRANGEMENTS FOR OFFICER RIVERA

Visitation will be held 3 p.m. to 9 p.m. Thursday at Elmwood Chapel, 11200 S. Ewing Ave., Chicago.

Funeral prayers will be at 9:15 a.m. Friday at Elmwood Chapel. Funeral Mass starts at 10 a.m. at the Church of the Annunciata, located at 11128 S. Avenue G, Chicago.

For more information visit Elmwood Funeral Chapel and Crematory.