Thank you for your answers!
I have an other question about Death Note. In the trailer of l-change the world, L says, at the very beginning, "Nihon he mukau tehai wo shite kudasai. [...] 97% no kakuritsu de kira wa nihon ni imasu. Koko ni wa modorenai kamoshiremasen ne".
What does tehai mean? I've found it is a noun meaning "arrangement", but then I couldn't translate the phrase.
And is there a difference between "modoru" and "kaeru"?