How did a young boy go from killing his mother to being somehow reformed to being sentenced to death all before he ever saw the age of 30? This is definitely one to look at and question.
https://s-a-ozbourne.medium.com/7-horrifying-japanese-serial-killers-4656c4481ec4
https://morbidology.com/the-osaka-sister-killer-yukio-yamaji/
https://murderpedia.org/male.Y/y/yamaji-yukio.htm
https://s-a-ozbourne.medium.com/the-story-of-one-of-japans-youngest-serial-killers-d5220db20cb8
https://www.jiadep.org/Yamaji_Yukio.html
https://www.japantimes.co.jp/news/2006/05/02/national/man-pleads-guilty-to-murdering-sisters/
https://www.dailystar.co.uk/news/world-news/possessed-killer-murdered-sisters-remember-27549696