Eiko (Asako Dodo) is a villainess from "The Bank Robber's Hospitalization Case", episode 4.09 of Case Closed (airdate February 16, 1998). She was the sole female member of a five-person gang of robbers, targeting a bank where Yoshio Sekiguchi worked. After making off with a million dollars, Eiko and her accomplices were driving away when they were involved in an accident. One of the robbers, Goemon Akabane, was injured in the crash, with Eiko and the rest of the robbers fleeing the scene while Goemon was placed in Beika Hospital.
Wanting to silence Goemon before he sold them out to the police, Eiko and her remaining accomplices plotted to have him killed. To do so, the evil Eiko kidnapped Yoshio's young daughter Yumiko and took her to the Beika Mall, which was across the street from the hospital where Yoshio was visiting his father (a roommate of the injured Goemon along with detective Kogoro Mouri). There, Yamamoto (the criminal group's leader) gave Yoshio a gun hidden in a box of candies and ordered him to kill Goemon, threatening to have Eiko kill Yumiko if he failed to heed their orders. But all along, the evil gang planned to kill Yoshio and Yumiko after their orders were met to tie up all their loose ends.
As Yoshio considered going through with the gang's demands to save Yumiko, Conan Edogawa (who was at the hospital visiting Kogoro and had deduced what was happening) helped expose the robbers and defeat them. When Takagaki (another conspirator) ran from the hospital and tried to call Eiko to have her kill Yumiko, Conan knocked him out with his stun gun watch before knocking Eiko out by kicking his soccer ball up towards her on the roof. Yumiko was returned safely to Yoshio and Eiko was presumably arrested offscreen along with the rest of her villainous cohorts.
- In the English dub, Eiko's name is translated as Shannon and is voiced by an uncredited actress.
- Asako Dodo previously provided the voice of villainess Yuko Ikezawa, who appeared in Season 1 of Case Closed.