Detective Conan - Season 1 Episode 626 : The Screaming of the Operation Room (2)

Conan investigates the scene and deduces Tadami was already dead before they arrived in the room and that the culprit feigned her convulsion in order to fake the time of death. He tranquilizes Sonoko and explains his deductions to the police revealing the culprit went under the table and used his feet in place of Tadami's which caused the convulsion. He declares Tsujiei as the culprit, evidenced by Tsujiei's toe nails which were painted red to match Tadami's feet. Tsujiei confesses and reveals Tadami encouraged their terminally ill friend into suicide a month ago because she wanted to see a person die.