Police and volunteers spent the weekend searching around the apartment complex playground where Jorelys Rivera was last seen.
On Monday, a special unit of law officers trained in child abductions joined the search for the child, a state official said.
There's evidence to suggest at this point that it may be an abduction," Georgia Bureau of Investigation spokesman John Bankhead told The Associated Press on Monday.
Jorelys was last seen around 5:00 p.m. Friday, while under the care of her teenage babysitter at the River Ridge apartments in Canton. The babysitter was also watching Jorelys' two siblings.
Probation officers and deputies also canvassed the area for registered sex offenders.
Investigators are working with school officials to compile a list of family and friends the girl knows. They also examined the family van on Sunday.
Officials say they have not ruled anyone out as a potential suspect in the case.
Jorelys was last seen wearing a pink shirt, blue jeans and black boots. Police do not believe she would have access to a change of clothes on her own.