CHICAGO (CBS) — Authorities Friday night announced a $3,000 reward for information that leads police to the killer of a longtime Ford assembly plant employee and her son, who were fatally shot in Calumet City earlier this week.

Police responding to a call of shots fired around 3 p.m. Wednesday near State Street and Freeland Avenue in Calumet City found Seretse Robinson, 48, and Leon Perry, 19, inside a car that had rolled onto the sidewalk.

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Robinson was taken to Franciscan Health in Hammond, Indiana, where she died about a half hour later. Perry was taken to Advocate Christ Medical Center in Oak Lawn, where he was pronounced dead at 6:33 p.m.

“It’s just hard to describe how much we’re going to miss her, because she was the glue that kept our family together,” said Robinson’s sister, Adele Marie Coldman. “I dont’ know what we’re going to do about the holidays without her. Just thinking that far ahead, it’s painful.”

Coldman also said her nephew will be “sorely missed.”

“Him and his mother were two of a kind. They couldn’t live without each other,” she said.

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Robinson worked at the Ford assembly plant in Chicago for more than 25 years. She was shot about a mile away from work.

United Auto Workers Local 551 described her as “loving, funny, and caring.”

“She would quite often go out of her way to help anyone or just simply say something to cheer you up,” the union wrote in a Facebook post.

The reward for information in the case was announced Friday evening at a news conference in Calumet City.

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