The House in an Aquarium

Agasa takes the Detective Boys to the house of a famous aquarium designer, Nishida. Kousuke Imura lets them into Nishida's home when Nishida does not answer the door. The Detective Boys find Nishida drowned in his bathtub. The police determine that Nishida died the night two days prior and from falling asleep in his bathtub due to alcohol consumption. Conan's disproves the theory explaining that the bathroom light was not on when they found him.