Berkeley County sheriff's spokesman Dan Moon says the remains were being examined Thursday at the Medical University of South Carolina in Charleston.
Sheriff Wayne DeWitt says investigators were led to a trash bin in Bowman after interviewing the father of Rodricus Williams and the father's girlfriend Grace Nichole Trotman.
Charleston police spokesman Cpl. Fred Bowie said Trotman has been charged with reporting the boy missing after police determined he was never in the Battery area of the historic city.
The boy's father, Roger Anthony Williams, was arrested early Wednesday on several bench warrants.