Katshuhiko’s heart literally stopped on Valentines Day. And beside his dead body, a cigarette and a chocolate bar were found among his usual items.
Before the tragedy, he was in his small party where they ate and drank. In lieu with Valentine’s day, each girl gives a guy a bar of chocolate, to which the guy would consume preferentially.
After putting Inspector Kogoro to sleep with a stun-gun wristwatch, Conan, using the voice-changing bowtie, revealed how Katshuhiko’s real killer was his mother.
Katshuhiko does not smoke with filters, that’s why Naomichi’s attempt to poison him through this, failed. Meanwhile, his mother knew his habits, and put poison in his coffee, knowing that he wouldn’t eat the antidote in the cake. She also framed Yoshimi by switching the chocolates she gave him with a half-eaten bar that Katshuhiko apparently ate. Though his mother immediately washed all the cups and switched the chocolates, poison lingers much deeper than the naked eye could see.
When her husband’s business took a turn for the worse, she had to think of the quickest way to acquire Katshuhiko’s estate, and save the house.
Katshuhiko is an orphan who was adopted by his only living relative when he was a kid. His foster mother knew he fell in love with Yoshimi since she closely resembled his deceased mother, so she framed her.
