Helen M. Ford, 51, is charged with murder for the death of her granddaughter, Gizzell Kiara Ford, the Chicago Tribune reported.
Gizzell was found dead in her home Friday after paramedics received a call that the girl was not breathing.
Prosecutors said paramedics found old and new wounds on the girl's body, allegedly inflicted by her grandmother, who was her primary caregiver.
An autopsy found that Gizzell died of strangulation and multiple blunt trauma injuries from child abuse and child neglect.
Ford initially told police Gizzell had injured herself because her mother didn't visit her very often.
However, police charged Ford with murder and Criminal Court Judge Adam Bourgeois Jr. Sunday ordered Ford held without bond.
Ford is also being investigated for possible neglect of the girl's two brothers, ages 12 and 9, officials said.
Meanwhile, Gizzell's family said they are shocked by what allegedly happened.
"Everybody is in shock," said Gizzell's uncle, Osvaldo J. Mercado, 30.
Sandra Mercado, Gizzell's mother, said she trusted Ford to take care of her daughter.
"She reassured my family that Gizzell was safe," Mercado told the Chicago Sun-Times. "Gizzell would always be safe."