Midori Goto (Takumi Kurebayashi) is the villainess of "The Disappearing Weapon Search Case", the Season 6 premiere of Case Closed (airdate February 15, 1999). She was the manager of the Midori Beauty Salon and the boss of Mika Mitsui, a stylist at the salon.
The episode began with Conan Edogawa and his friends arriving at the salon (Ayumi Yoshida being a regular customer) just as Midori and Mika were exiting. The women were in the midst of an argument, as Mika had just informed Midori that she was accepting a job at another shop and was quitting. Outraged, Midori proclaimed that she wouldn't allow her to leave before storming back into the salon.
Later on, Midori went to Mika's apartment and attempted to convince her to come back, leading to an argument in which Mika threw a hanger at Midori and scratched her. Enraged, the evil Midori used the hanger to strangle Mika to death and disposed of the murder weapon in the garbage afterwards. When Conan and company discovered Mika's body, Midori was called in to identify her, with Conan (and later on, inspector Juzo Megure) suspecting Midori due to her nervous behavior. A piece of plastic under Mika's fingernail pinpointed a hanger being used to kill her, but a search of the garbage showed that that the hanger was gone, allowing Midori to leave after without being arrested.
Later on, though, Conan deduced that a crow had used the hanger to build a nest and eventually found the missing weapon. After handing the weapon over to the police, Midori was brought back in for questioning, with the blood she left on the hanger's tip during her attack on Mika sealing her fate. Cornered, Midori confessed to killing Mika, revealing her anger at Mika for (in her mind) abandoning her and not appreciating her for having trained her. Juzo responded by angrily lambasting Midori for resorting to murder for such a trivial reason before arresting her.