Hill was found dead Monday night and police say he had been inside the van for almost 12 hours.
"This was an absolute tragedy that could have been prevented", he said.
She then picked up another child and drove to the Little Miracles Academy location on West Colonial Drive.
About three hours later, St. Charles provided a sworn statement to Orlando Det.
UPDATE: Deborah Denise St. Charles, 51, has been arrested for Aggravated Manslaughter of a Child in the death of 3 year old Myles Hill. Police did not say what the procedure of the day care center was whenever children were not present for the day.
St. Charles told police that she exited the van and opened the rear hatch to grab some cleaning supplies she was supposed to deliver to the day-care center.
During the pickup, Myles' grandmother, Brenda Watts, provided St. Charles with the payment for Myles' childcare and placed him in the back of the van on the driver's side, the affidavit states.
Orlando police received a call at 8:30 p.m.in connection with a possible child neglect case at Little Miracles Academy at 900 Plymouth Ave., Sgt. Eduardo Bernal said. She was not an approved driver for the center.
Florida authorities are temporarily shuttering two day care centers connected to the death of a 3-year-old-boy. The arrest affidavit says St. Charles walked away from the van into the day care center, leaving inside Myles, who was weeks shy of turning 4. Investigators recreated a simulation of what the heat was like in the van on the day Myles died, and found temperatures reaching 144 degrees.
The medical examiner listed the cause of death as "hyperthermia due to environmental exposure" and the manner of death as an accident. We are conducting a thorough investigation and are assisting law enforcement with their criminal investigation.
Little Miracles Academy "was previously cited for not keeping proper paperwork", Carroll said. "We will continue to aggressively act to keep kids safe and will hold anyone accountable who doesn't follow the law".
According to Orlando police, Myles was picked up Monday morning with other children and was supposed to be dropped off at another Little Miracles location instead of the one he was taken to.
DCF officials said anyone who drives a vehicle for a day care facility must meet certain requirements.