The investigation could take eight months to complete
A total of 206 bodies have so far been discovered dumped at the Tri-State Crematorium, and officials believe the final toll could exceed 300.
Officials say they plan to drain a small lake behind a house belonging to the crematorium's operator, 28-year-old Brent Ray Marsh, after finding a skull and torso in it on Wednesday.
Georgia Bureau of Investigation director Milton Nix said crews were using underwater cameras to scour the lake, about 650 feet (200 metres) from the crematorium.
Mr Marsh - who took over the crematorium from his parents in 1996 - has been charged with 16 counts of theft by deception for accepting payment for cremations he did not perform.
If convicted, he faces between one and 15 years in jail on each charge.
Anxious relatives, meanwhile, are continuing to arrive at the town of Noble to discover whether their relatives are among those who never received a proper burial.
Just 36 of the bodies recovered have been positively identified and officials say the names of some will never be known.
Officials have found skeletons inside sealed vaults, bodies scattered in woodland and corpses that had been dragged into a shed.
Some of the deceased are estimated to have been left for up to 15 years.
The bodies range from the newly dead to severely decomposed, even mummified, said Kris Sperry, the state's chief medical examiner.
Relatives' ordeal
The families of the dead believed that the cremations had taken place as planned.
But when officials examined the contents of 51 urns that had been sent to relatives, they found that some contained powdered cement or potting soil rather than human remains.
Other urns appeared to contain human remains, but it was not clear whose.
One woman who for the last 18 months has worn a locket containing what she thought were her husband's ashes said she felt "doubly robbed".
"I felt all along that I had a little of him with me," Bobbie Cann said.
Now, as the body count keeps growing, angry relatives have been arriving at the emergency centre set up at the sheriff's office in Noble, clutching photographs, x-rays and dental records.
The case came to light last week when a woman walking her dog in woodland in the area found a skull.
A federal disaster team has now moved in to the crematorium.
The teams are trained to deal with the aftermath of disasters like air crashes, or the events of 11 September in New York.
Investigators say they are likely to be at the site for another eight months.