cooper harris in georgia. the child left by his father justin ross harris, who spent the day working at home depot, having lunch with friends and sexting women, all while his son spent seven hours strapped into the car seat, scratches to his face, abrasions on the back of his head. the child apparently struggling to survive the heat. joseph scott morgan is a forensic scholar and forensic investigator. you still have a child strapped in a car that s exposed to extreme heat that i can assure you no adult would be able to endure. i certainly couldn t endure it. reporter: car ks can heat up very quickly, even in cooler temperatures. 91 outside, inside we ve only been in here about ten or 15 minutes and it s 108. i m sweating through my shirts already. i m sweating just about everywhere. these cars can go from uncomfortable to deadly very fast. and then there s this case out of washington, d.c. did you leave her in a car? .