The Department of Children and Families said Wednesday night it had been working with members of Chevonne Thomas' family to support the woman and her son, who were reunited under a court order in April.
Police on Wednesday found the decapitated body of 2-year-old Zahree Thomas on the first floor of the Camden rowhouse he shared with his mother.
Chevonne Thomas fatally stabbed herself in the neck after calling 911 to report her son's slaying, authorities said.
Thomas told the 911 operator that she used to take the antidepressant Prozac.
"I didn't take it today, but I should have," she said, according to a recording of the rambling, often incoherent call released Wednesday evening.
She also initially blamed her son's grisly death on her boyfriend, but quickly recanted.
"You know what, I did it, I'm lying, I'm lying, I'm lying, I did it," she said.
The Department of Children and Families supervises more than 7,000 children living in licensed foster and group homes.