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. The police investigate Imura's alibi which confirmed he was in Guam for the past two days at a shooting range. Conan investigates and realizing how the murder is done, impersonates Agasa's voice and declares Imura the murderer. He explains that Imura used the cooler from the shrimp's tank to fake the time of death, evidenced by the wet glue that has yet to dry on Nishida's fingertip and the dead shrimps in the same aquarium.