Was Cooper Harris still alive when dad first returned to hot car?

David Brani, a mechanical engineer with expertise in heat transfer, conducted heat research on Justin Ross Harris' SUV. He testified at Harris' murder trial at the Glynn County Courthouse in Brunswick, Ga., on Wednesday, Oct. 19, 2016. (screen capture via WSB-TV)

Credit: WSB-TV

Credit: WSB-TV

David Brani, a mechanical engineer with expertise in heat transfer, conducted heat research on Justin Ross Harris' SUV. He testified at Harris' murder trial at the Glynn County Courthouse in Brunswick, Ga., on Wednesday, Oct. 19, 2016. (screen capture via WSB-TV)

BRUNSWICK — Inside his father's SUV, where 22-month-old Cooper Harris had spent more than three hours on June 18, 2014, the temperature was a stifling 98 degrees, according to testimony Wednesday from a heat expert contracted by the state.

It was 10 degrees cooler outside at 12:45 p.m., when Justin Ross Harris returned to his 2011 Hyundai Tucson to drop off some light bulbs. Prosecutors say he intentionally left Cooper inside the vehicle; the defense contends it was a mistake.

On Tuesday, former Cobb County Medical Examiner Brian Frist testified "Cooper could've survived" the morning as long as temperatures remained in the 90s inside the car. But there is no way to pinpoint an exact time of death, Frist said.

“He could’ve died before noon. He could’ve died after noon,” defense attorney Bryan Lumpkin asked Frist under cross-examination. “We just don’t know.”

Regardless, the state wants jurors to consider the possibility that Harris had gone to his car to check on Cooper’s condition.

If the boy was not yet dead, he soon would be. The temperature inside the car would peak at 125 degrees around 3:30 p.m., said David Michael Brani of Applied Technical Services, the state’s expert. Harris told Cobb police he discovered his son’s lifeless body less than an hour later when he left work.

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