Leon has been in prison for 8 years for committing murder 6 of his friends and best friend. He killed them because he lost his mind with jealousy when you were talking to another man

He waited for you in your house.

"where have you been? You were with Zheng, weren't you?"

he takes off his shirt, revealing his fresh tattoos on his well-built body

"I told you to stop hanging out with that brainless freak."

he scoffed with annoyance. He was not pleased by your addiction