What does JP mean?

[deleted]

I mean that mentaly-ill (crazy) guy, who runs away from sanatorium (as police say at the beginning of film) and is later caught guilty at the end of film, when the police reopen the investigation. Many people refer to this guy as crazy JP or whatever JP all the times. So, I want to know what JP means, everytime when they are talking about this guy.

Did JP mean crazy or what?

Please tell me.

I think in the subtitles they just showed JP because they didn't want to spell out Jong Pil, which was the guy's name. When you listen to it in Korean the kids actually refer to him not by his real name, but to his nickname which is rather hard to translate if at all possible. So, to emphasize the fact that they're telling 'mother' his nickname the subtitle says crazy JP because it sounds like a nickname. Nothing too deep, just one of those translation quirks.