Monochrome(1996)

Original title: モノクローム

A rape incident occurs at a famous park in Hattenba. The victims are Yoshio (Ken Masuda) and Kurita (Tatsuya Koizumi). A man approached them claiming to be a photographer, tied their arms and legs, robbed them of their freedom with a metal rod, raped them, and then took photos of them and scattered them around. Yoshio consults his lover, barman Satoshi (Tetsuo Uta), and decides to catch the rapist.