Grannis has accused the agency of withholding vital information in the Shaniya Davis case.
Davis, 5, was taken from her Fayetteville home in November 2009. Mario Andrette McNeill has been charged with kidnapping, rape and murder. He was seen on a hotel surveillance video with Davis.
The girl's mother, Antoinette Davis, is charged with child abuse involving prostitution.
At a news conference late last month, Grannis said problems started the day Davis was reported missing when DSS left detectives waiting hours for assistance.
"It was critically important that DSS cooperate in every way to save the life of this child, it does not appear that occurred," said Grannis.
Eventually, he said it took two court orders to force DSS to handover missing documents that were not included in an initial report to the DA's office.
But in a written response Friday, the Cumberland County Social Services Board said there was no delay.
"We have concluded that the agency worked diligently with the Fayetteville Police Department to provide all information," says the statement.
The statement also says the DSS director also "unequivocally denies" alleging a Fayetteville police officer tried to break into DSS offices to obtain information.
The statement says the incident never occured.
Grannis has enlisted the help of the Cumberland Co Sheriff's Office to review the DSS handling of the case in order to have "a set of fresh eyes" on the matter.