There can be no reason that most would find acceptable...he was evil. Some people are. He left a trail of broken hearts behind him. From what I hear, he didn’t watch the son and was at fault for the accident. He meets a woman and never tells her about his son? He deliberately targets children while wearing a Santa suit? chilling! He is evil there is no other explanation that could ever make sense of this... pure evil.
No criminal record. Well educated, worked for NASA. Not exactly a profile of evil.