ROCHESTER, N.Y. -- The medical examiner has ruled the death this week of Brook Stagles, a 3-year-old girl, as a homicide, according to the Rochester Police Department.

Brook's maternal grandfather, John Geer, said he believed Brook had been beaten to death; that family members knew right away when they saw the little girl at the hospital that she had died at someone else's hands.

Geer says Brook had been living with her father, Michael Stagles. Stagles did not want to talk to Time Warner Cable News when cameras went to his house on Thursday.

Geer believes Brook was beaten to death while she was living with her father and his girlfriend, Erica Bell. We've learned Erica has been in jail since Saturday on unrelated charges.

The court stated Bell pleaded guilty to previous charges of possession of stolen property. Bell was re-arrested and sent to jail after missing a court date.

John Geer, his daughter Ashley, and other family members said they started recently noticing bruises on Brook, including one time, marks around her neck like someone had tried to strangle her. Geer says there was an open Child Protective Services investigation. 

According to Geer, Michael told him last Wednesday that they thought the little girl had the flu. Sunday was the day Brook was taken to the hospital. She died the next day from internal injuries.

Geer says she was so covered with bruises that doctors asked if she had been in a car accident.

John says Child Protective Services was negligent. The agency would not discuss any case under investigation.

"I know they're sourced out and I know they're busy, and I know that people make false claims and that does clog everything up for them and they can't figure out who is who and what is what," Geer said, "but I know that with this case, they were on it long enough and they had enough time to figure it out.

"I'm going definitely fight to make sure something that there is something put in place that this will never happen to another child again."

No one has been charged.

GoFundMe page has been established to raise money on "behalf of other families in this situation," with proceeds donated in Brook's honor.