The girl, was allegedly fatally stabbed by her own mother in East Garfield Park Saturday morning, police said.
On Sunday, the Cook County Medical Examiner ruled the girl's death a homicide.
The medical examiner's office identified the girl Saturday night as Serenity Arrington.
Police have identified the girl's mother as 27-year-old Simone Austin.
Chicago police spokesman Tom Ahern confirmed that Austin was Arrington's mother Sunday evening.
Austin was arrested Saturday morning in the 3200-block of W. Fulton Blvd.
The girl received multiple stab wounds to the neck, according to the medical examiner.
The young girl's grandfather claims his 27-year-old daughter is responsible for fatally stabbing her daughter on Chicago's West Side.
Sylvester Washington said his granddaughter loved alphabet soup and watching movies with him.
"Y'all would have loved her. Sweet little girl. Man. Granddaddy little girl," he said.
Washington is now trying to understand how his beloved little granddaughter was taken from him. His neighbors offered their support and shared shock.
"To hear something like this happen on this block is just mind-blowing," neighbor Melanie Weaver said. "It's devastating. I couldn't imagine the pain and the devastation you know that they feel."
Chicago police responded just before 9:20 a.m. to the 3200-block of West Fulton Boulevard for a person stabbed.
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When officers arrived, they found a 5-year-old girl with stab wounds being treated by Chicago fire officials.
"We're still trying to figure out what happened at this time; all we know is the victim and the suspect were in the house," said Jose Jara, with the Chicago Police Department.
They also said the suspect was likely in the house with the girl at the time of the incident.
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Chicago fire officials transported the girl to Stroger Hospital with "multiple stab wounds," where she died a short time later.
"It's horrible, man. My own flesh-daughter did that. Man. Y'all don't want to have this feeling. No, I can't explain it," Washington said.
"It's a baby. She's 5 years old, getting ready for pre-K and all those things that she will never get to experience and her mom, she still had a whole lot of life in front of her so it's just like two lives lost," Weaver added.
Friends of the family said they are offering whatever support they can to help this family heal.
"For it to be somebody that young and that I have interacted with... It's like man, c'mon now, I didn't see this," family friend Darnell Richardson said.
Austin is facing charges for first-degree murder and is due in court Monday.
Sun-Times Media Wire contributed to this report.