Transcript for Premeditation Considered in Georgia Infant's Hot Car Death
And now shocking new details in the case of Georgia father charged with murder after leaving the toddler in a blistering hot car. He claims it was an accident, and there are online searches from both parents. We should warn you, this is a difficult story. O Reporter: And two Georgia parents who died of heatstroke, forgotten in a hot car. Both the boy's mother and father searched the internet for information on children dying in hot cars before their son died. Georgia police say that 33-year-old Justin Ross Harris said he strapped his son cooper into a rear-facing car seat on June 18th, was supposed to drop him off, but seven hours later, he noticed his life lesson in the backseat. Witnesses say he was desperately trying to revive him. He kept say, what have I done. Reporter: Georgia police immediately arrested him, he is due in court on Thursday. He has pleaded not guilty. If he deliberately forgot the child, may god have mercy. Reporter: They researched child deaths, and the temperature. It explained because he was fearful that could happen. His attorney told ABC news he does not have a comment at this time. It's devastating evidence to overcome. Reporter: And Leanna Harris made similar statements with research on car deaths and how it occurs. She has not been charged, and has not return ABC's request for a comment. And Justin Ross Harris spoke from jail to friends and family gathered for cooper's funeral. There are no words to come out of that piece.
This transcript has been automatically generated and may not be 100% accurate.