Investigators said Logan Starling, the son of Butler's boyfriend, was left inside a hot SUV in the parking lot of the Elite Preparatory Academy in October 2018.
Detectives said four other children got out of the SUV and went into the school at about 8:20 a.m., but Starling didn’t exit the car.
Court documents show Butler, who worked at the school, was asked during the day where her stepson, Logan, was. The documents also stated that it wasn't until she was asked again at the end of the day that she realized the child was still in the car.
>> On WFTV.com: Stepmother of boy who died in hot SUV quits job after receiving death threats
Authorities said Butler found Starling in the third row of the SUV, leaning against the window with his eyes closed.
The school's director carried Starling to a nearby fire station, authorities said. Starling was then taken to a hospital, where his body temperature was recorded at 108 degrees. For perspective, doctors say a fever above 104 degrees can cause brain damage.
The investigation also showed the inside temperature of the car was 121 degrees when the boy was removed. Investigators believe he was in the car for six hours.
Butler claimed she remembered Starling getting out of the SUV and that she locked the doors when they were walking into the school.
>> Read more trending news
Documents said Butler believed Starling got into the SUV later, but she wasn’t sure how. She said during an interview that Starling suffered from autism and was known for wandering around.
But arrest documents show Starling’s teacher disputed that claim, and video showed the child never left the SUV.
"You were arrested pursuant to a probable cause capias, where probable cause was previously found for the offense of aggravated manslaughter of a child and neglect of a child,” the judge said in court.
Butler was ordered to remain in the Orange County Jail on $15,000 bail.
Logan's family believes the bond was set too low. Butler was later able to bond out of jail Wednesday evening.
"Six months of no punishment for Mariah seemed like six years," said Logan's great grandfather Roy Werner. "But six months of Logan being gone seems like six days."