Case Closed - Season 1 Episode 736

Since Kataoka is a big fan of Mouri, the crew got invited to Kataoka's house. While all the people got gathered in the garden, Kataoka, disguised as 'Kaito K', insisted Mouri and others to find him as a seeker during the hide and seek in his house. After hearing Kataoka scream, Conan, Ran, and Seiya head in the direction of the sound to find Sada holding the deceased Kataoka. It appears Kataoka died after receiving blunt force trauma from falling off a ladder.