He is from a well-to-do Japanese family, has lived all his life in privilege. He is well-educated, artistic, and cultured.
He is a cannibal.
Read his confession here.
As always, a morsel to tease your palate;"...I cut her body and lift the meat to my mouth again and again. Then I take a photograph of her white corpse with its deep wounds. I have sex with her body. When I hug her she lets out a breath. I'm frightened, she seems alive. I kiss her and tell her I love her. Then I drag her body to the bathroom..."
He walks free now.
If a soft-spoken Japanese gentleman invites you to his place to read some German expressionist poetry, it's probably wise to stay home.