Nobody must enter the room where Gōzō Hatamoto has been found death. After knowing how long Gōzō has been remained lifeless, Kogorō asked the butler Suzuki where he was at the time of Gōzō's death and further questions. Kogorō then reveals that Gōzō's room is entirely impenetrable which the family members of Gōzō all think that it can be suicide. Kogorō then ask the family members if he had a reason to kill himself, which Natsue tells Kogorō that Gōzō would never commit suicide. Kogorō then said that there should be a weapon next to Gōzō's body if he should commit suicide. The entire family members than starting to cause a uproar and evenly are still believing that it is suicide. Conan reveals that it is murder and helps Kogorō investigate a lot further which Conan also helped him that Gōzō was the one who locked himself up. Afterwards, Kogorō came to believe that one of the seven family members should have killed Gōzō, which Suzuki tells Kogorō that he has found a flower which Natsue tells Kogorō that it was the flower that she put on Takeshi which Takeshi became the suspect behind Gōzō's murder. The family members starting to reveal Takeshi's true nature which Natsue starting to runs away from Takeshi which Takeshi is trying to explain but couldn't. Conan then finds a evidence in Gōzō's blood.