Once at the scene, officers located the victim, later identified as 41-year-old Clarice Alexander, unresponsive and officials pronounced her dead.
An investigation is ongoing and police have not released further details.
The victim's sister, Chianni Hopkins, told the station she was on the phone with Alexander a short time after and could hear concern in her voice.
Hopkins said her sister saw a man who she believed was stalking her.
"She said, 'Why he just rush me?'" Hopkins recalled about the phone call. "And, she said, 'Oh my God, this is him. Call you back.”
That return call never came. Hopkins said her conversation with Alexander was terminated at 8:27 a.m. and a call to police from a person who found Alexander shot came in at 8:32 a.m.
A neighbor said surveillance camera footage of the attack shows the suspect fleeing in an older model gray Chevy Malibu with heavy front-end damage. The neighbor turned the footage over to the Hanover Park Police Department.
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Family said Alexander was familiar with the shooter and called police on the man multiple times in the past.
"She still had to call the police on him that night," Hopkins said. "He killed her that next morning."
"She had babies," she noted. "She has a one-year-old grandson. She was just starting to enjoy... honestly, I can't put it in words."
The shooter remains at-large and anyone with information is urged to contact Lieutenant Ralph Gniewosz at (630) 823-5516.
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