I decided to use a line which is, or was, probably most commonly used by the police; "What's all this then?"

I used Worldlingo for this task.

English -> Dutch
Wat is dan dit alles? (translated back to English: What is then all this?)

Dutch -> Swedish
Är vad därefter all detta? (translated back to English: Is what then all this?)

Swedish -> Greek
Είναι τι έπειτα όλο αυτό; (translated back to English: He is what then all this?)

Greek -> Korean
그는 그 후에 이것 모든 무엇인가?

Korean -> English
Is he this thing all what after that?

Appearantly the Greek and Korean translations are worse than translations to Dutch and Swedish, they should work on that.