IWGP - Ikebukuro West Gate Park, Volume 4 (v. 4)

Makoto and Fujio are still hitting a brick wall searching for Princess. After some bizarre text messages come in on his phone, Makoto tracks down Guriko, a girl he went to middle school with. She's highly intelligent but a social hermit, and she just happens to have surveillance tapes of the convenience store where Princess was last seen. It turns out that Princess is dead, her body dumped off a remote road. Once Fujio finds this out he takes justice into his own hands.