Conan investigates and upon discovering the method, tranquilizers Kogoro and explains how Hoshie committed the murder. He explains the burn marks on Hoshie's napkin indicate cyanide was on the napkin and the poison was placed on a lemon slice. Conan elaborates by explaining how Taruto was famously known to hate sour things and had planned to surprise his guest by eating sour food with the use of synsepalum dulcificum.