I am trying to find an episode that i really want to watch but cant find the episode of.

this episode is about a woman found died in the middle of a ritual 表, テーブル of some kind. i think she might have been blonde with curly hair. and the trick that was used to kill her involved rolling up a poster board and sliding it in a small window above the door of the room. And in the end the police tore down the place and found a body of a man that they couldnt find years ago. Also in the beginning of the episode the original people who were there were dressed in black cloaks for some type of ritual.
P.S i think this is a two parter!