The investigation into what caused twin 4-year-old boys from north Forsyth to fall seriously ill continued today.
Forsyth County Sheriff Ted Paxton described the situation as a "complete mystery."
"With everything they've done at the hospital, the doctors are just in a quandary," Paxton said. "They just cannot explain it."
He said preliminary toxicology tests did not come back positive for dangerous substances in either of the boys, who are being treated at Children's Hospital of Atlanta at Egleston.
The twins, whose names have not been released, were taken there Monday after coming down with similar symptoms.
According to Paxton, one of the boys was listed in guarded condition while the other was stable. "Guarded" is worse than "critical" condition, he said.
No charges have been filed in connection with the illnesses. The sheriff said authorities are involved to ensure nothing criminal has happened to the children.
Paxton said emergency personnel were called about 7:30 a.m. Monday to a residence on John Burruss Road, where a 4-year-old boy was unresponsive and having respiratory problems.
Once the child was en route to the hospital, the mother, whose name has not been released, dropped off the other twin and a 2-year-old sibling at a baby sitter's house on Little Mill Road, Paxton said.
She then headed to the hospital.
The sitter called 911 sometime between noon and 1 p.m., Paxton said, when the other twin started showing similar symptoms as his brother.
That child and the 2-year-old were also taken to Egleston.
Paxton said the younger child had been evaluated by doctors and, as of this morning, did not appear to be sick.
He said the first child to be taken to the hospital was in the more serious condition.
Investigators are working with medical staff to try to figure out what has made the boys ill.
"Everybody's working together to try to establish what happened but as of this morning, it is still a complete mystery," Paxton said.