CHICAGO (CBS) — A mother and her son were fatally shot Wednesday afternoon in south suburban Calumet City.

Officers responded to gunfire in the 500 block of State Street at 2:48 p.m. and found 48-year-old Seretse Robinson-Perry of Chicago Heights and 19-year-old Leon Perry of Lansing shot, according to authorities.

Robinson-Perry was taken to Franciscan Health in Hammond, Indiana, where she died at 3:31 p.m., according to the Lake County coroner’s office. Her son was taken to Christ Medical Center in Oak Lawn, where he died at 6:33 p.m., according to the Cook County medical examiner’s office.

seretse robinson and leon perry Mother, Son Fatally Shot In Calumet City Were Not Targets

Seretse Robinson and Leon Perry (Source: Facebook)

Both of their deaths were ruled homicides.

Community activist Andrew Holmes was offering a $3,000 reward for information leading to the arrest and conviction of those responsible.

Holmes said investigators don’t believe Robinson-Perry and her son were the intended targets of the shooting, and said he believes the shooting may have been a case of mistaken identity.

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Calumet City police were not immediately able to confirm Holmes’ information Saturday evening.

In a statement, police said the shooters fired from a dark-colored Infinity FX-type vehicle that drove away headed west on State Street after the shooting.

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An image released by Calumet City police of a vehicle used in the fatal shooting of a mother and her son on Wednesday in the south suburb. | Calumet City police

The South Suburban Major Crimes Task Force was assisting with the investigation. Anyone with information was asked to call police at (708) 868-2500. Tips can also be submitted to Holmes’ organization at (800) 883-5587.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2017. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)