The 7-year-old girl who allegedly killed an infant at a Garfield day care center Friday had anger-management issues, said Lt. Dan Herrmann of the Pittsburgh Police Major Crimes unit.

Police say the girl, who is day care operator Loretta Bray's granddaughter, took 10-month-old Marcia Poston from her baby seat and threw her on the carpeted cement basement floor at least twice.

A 20-year-old caregiver was supervising the five children at the center but had gone upstairs for a few minutes to change a child's diaper. She returned downstairs when she heard a commotion and found Marcia on a loveseat with blood around her ears.

An autopsy determined Marcia died of head injuries.

Ms. Bray had left the day care center to go to a pharmacy for medicine for the 7-year-old, who was home from school sick.

Lt. Herrmann said she could potentially be removed from her home and placed in foster care, depending on the results of the investigation. But as a 7-year-old, she cannot be charged with murder.

"My focus is not on the 7-year-old for homicide," he said.