Responses
I think you're right, i think his mom and him left him hanging out there and the police told Sangwoo and his mom they found him out there. They probably thought it was a murder because of the autopsy or just outer visuals and Sangwoo and his mom either buried him there or told the police to after. I bet they reported him missing or some hiker found him. Just a theory though.
When Sangwoo killed his mother (who he loved ), the sense of guilt made him Crazy & psychopath. If he kill Bum it will be death of him.
I think he will not going to do the same mistake .