You are detective and the main villain is called Eric. A female is also with you and sometimes you can do her optional, yes its a optional game. From what i remembered, Eric's sister is called Rebecca also, people are dying with a mask sticked, yes STICKED to their faces. And Eric, in the past when he was a little boy, he killed his sister, Rebecca and made a mask and sticked it to her face. It's a optional game(where you do a lot of options and the endings depend on the options)