S1E604 : The Seance's Double Locked Room Mystery (Second Locked Room)

Hoonogi reveals that he discovered Hirasaka in his room dead. Kogoro breaks open the room and confirms Hirasaka died from drinking poisoned wine. The police arrive at the mansion where Kogoro shows them both locked rooms. In the séance room, Kogoro explains that the front door was padlocked from the inside and the only way out is through high window. The high window can only be opened with a switch in the room. In Hirasaka's room, a small window is found above the door but too small to fit a person through. On the floor of the room were the ripped posters of Kira from the séance room. The keys to both rooms were found in Hirasaka's drawer. The police interview the club members and discover Hirasaka, Hoonogi, and Sawanami have received threatening messages from a fan of Kira and their goal with the séance was to find the culprit. They deduce that the one sending the messages, swapped the recording, is the same person who committed the murders.