A 19-year-old Tahlequah man was booked into the Cherokee County jail on complaints of child neglect and second-degree manslaughter over the death of his 18-month-old daughter Monday evening.
Police say Cody Butler was at a city park "visiting outside the vehicle" with the child in a car seat in the back seat of the car.
"It appears the father had the car running and the heater on. At some point, Butler noticed the child's cheeks appeared purple. Butler removed the child from the vehicle and CPR was started," said Tahlequah Police detective Jeff Haney.
The Tahlequah Police Chief said he's never heard of it happening before.
His investigators are testing whether a toddler left in a car with the heater on could have died from getting too hot.
"It's horrible. I mean, I'm a parent of six and I just can't imagine. You shouldn't outlive your kids," said Tahlequah resident Melinda Walker.
Investigators say the car was running and the heater was on, but not on full blast or on maximum heat.
They say at some point, Butler noticed the toddler's cheeks were purple and started performing CPR.
The little girl was taken to Tahlequah City Hospital, where she was reported as having an extremely high core temperature.
She was pronounced dead there.
"I didn't know that they could get too hot in a car in the wintertime. I mean, I knew about it in the summer, that's common sense, you would think, but not in the wintertime," Walker said.
The National Weather Service said it was about 50 degrees at 9 p.m. in Tahlequah on Monday.
"This is a tragedy that we don't ever want to see and rarely have here in the city of Tahlequah," said Police Chief Clay Mahaney.
He said, even though it's unclear how the baby died, she died after being left unattended and that warrants the manslaughter charge.
"I hope that people understand, no matter what time of year it is, summer or winter, you should never leave a child unattended in a vehicle," Mahaney said.
Security cameras show Butler was at the park for a couple of hours.
Detectives are recreating his version of what happened to see what the temperature in the car would have been and how long the child was in the car.
The child's body was taken to the Medical Examiner's Office in Tulsa to determine a cause of death.
Formal charges will depend on the examiner's report.