yeah. did ross love his little boy? yes, he did. very much. did you ever see ross express anger or hatred or malice toward his son ever? no, never. reporter: then came that terrible day. the courtroom was silent as leanna described arriving at cooper s daycare and being told he wasn t there. she said, he didn t come today. and i just kind of went into a panic. i didn t know what to do. i was just it didn t make sense. cooper was supposed to be at daycare. i was supposed to be the one to pick him up. it didn t make sense. the only thing that made sense to me, based on everything that i knew that day, ross must have left him in the car.
she texted her neighbor and asked her to just go look. she has a key to her apartment. just go look. see if he s there. and she was like, maybe the house will just be torn up. it had be a little toddler tornado when she gets there, but he ll be there. obviously, he wasn t. reporter: leanna rushed over to ross s office to see if cooper was there. it was at home depot that a police officer tracked her down. their conversation was recorded as he gave her the worst possible news. there ain t no easy way to tell you this. your child is deceased. i m very sorry to have to tell you that. where is my husband? your husband is up at our headquarters right now. reporter: the officer explained ross had never taken cooper to day care that day. that he d done the unthinkable, and left cooper in his car for seven hours in the georgia heat. has he ever done anything like that, forgetting about no.
appeal, vic reynolds, the top prosecutor in cobb county believes it won t change the outcome. i have complete confidence in the jury s verdict, complete confidence in the evidence that was presented, and i believe when the day comes, this verdict will, in fact, be affirmed. reporter: but ross harris s supporters say there is another tragedy in all this. they believe his conviction will make things worse for parents who make similar, terrible mistakes. this sets the precedent that anyone that does this is a monster. and that s just not the case. this really can happen to anyone. reporter: cooper s family may never stop grieving for the little boy who had just learned to say his dad s name, loved his trucks and loved to smile. what does leanna want cooper s legacy to be? that he was loved. he was very loved by everyone that knew him, especially his parents.
sexual chats happened on the very day cooper died. he was communicating with a woman right. reporter: ten minutes before he left with cooper? right. we were able to determine that he had been messaging at least six different women throughout that day, sending pictures of himself, asking for photographs. reporter: prosecutors believed ross harris was in the grip of an escalating obsession with sex. and they came to an awful conclusion. that ross wanted so badly to be rid of the constraints of family and fatherhood, he decided to kill his own child. does being a creep with women make him a child killer? absolutely not. in this case, though, it showed us the extent to which he was living the other life. it showed us how it had overtaken in his life what was important to him. reporter: so they threw the book at him. ross was indicted for malice murder, the first person ever to be accused of using a hot car to intentionally kill a child.
mother drove one block, a 30-second drive, and in a matter of that brief time forgot that her child was in the car. reporter: what we re talking about here, there is actually a name for this. this is referred to as forgotten baby syndrome, which actually describes a phenomenon in which normal, attentive and loving parents, for reasons we don t fully understand, lose awareness that their child is in a car. reporter: diamond says it can happen to anyone. distraction and exhaustion often play a role. he adds, once the child is forgotten, the brain plays a dangerous trick. what s remarkable about these cases is that these parents actually create sort of an artificial memory that the children are actually at day care and that they are safe. reporter: but in this case, investigators were increasingly convinced that cooper s death had nothing to do with a slip of the mind. there s been a lot made of how could you forget something that quickly. now, i don t know what was going