According to here, it is
かんがえ
ると
いずれしけいになるか
てまねきしているあい
つにころされるだけだ。
しってい
る。おれはキラのそんざいを。
えものにされる。
It is written from top-to-bottom, right-to-left; but in the typed version, it is rotated counter-clockwise 90 degrees.
I also noticed that つ got interpreted as っ in the hidden message (L知っているか).
I think it is spelt out as -
- 考えると、いずれ死刑になるか、手招きしているあいつに殺されるだけだ。知っている。俺はキラの存在を。獲物にされる。
- If I think about it, either I will receive death penalty, or only get killed about by someone who is inviting (faster, to the death bed, perhaps meaning Kira). I know. Myself, that of Kira’s existence. I got turned into a prey.
In particular, I am not sure about how to segment and translation of the first sentence.
It is later revealed in Vol 2, Ch 8 (first chapter of the volume), that there are more pages.