Muzan-e: AV gyaru satsujin bideo wa sonzai shita! (1999) - Daisuke Yamanouchi

From IMDB:
A female reporter researching underground sex films stumbles across a snuff film, and her further investigation causes the film makers to take action against her.

Sadistic Yoga (2006) - Daisuke Yamanouchi

The female instructor Mariko gives yoga classes at a high-class club in Tokyo. She has a crush on Rika whom she gives private lessons to. When she notices bruises on Rika's body, Mariko learns that the young woman is involved in a highly abusive S&M relationship. On order to gain the affections of her student, Mariko decides to take revenge against the men in Rika's life.