Yoriko Nakatani (Emi Shinohara) is the villainess of "The Great Dog Coeur's Triumph", episode 15.08 of Case Closed (airdate April 10, 2006). She was the wife of Haruhiko Nakatani and the daughter-in-law of his mother, Kinue. The Nakatanis were neighbors with Eisuke and Misato Tsutsumi, who owned a Irish setter named Musashi.
Yoriko was introduced asking Kogoro Mouri for his help as a private detective, claiming that Musashi was acting aggressively towards her for no reason and that she was afraid he would eventually attack her. Having just met the Tsutsumis and Musashi that day in the park with Kogoro's daughter Ran, Conan Edogawa asked Yoriko if she'd done anything to make Musashi angry at her, only for Yoriko to become offended and storm out, proclaiming that anything Musashi did to her would be Kogoro's fault. Later on, the Tsutsumis returned home early from a party to find Yoriko cowering in their yard--with Kinue's deceased body nearby.
An investigation found that Kinue bled to death from bite marks in her neck, with Yoriko claiming that Musashi attacked and killed her mother-in-law when she went to retrieve a shirt that fell into the Tsutsumis' yard while she was getting the laundry. She also stated that she believed Musashi mistook Kinue for her due to Kinue wearing Yoriko's cardigan, making it appear her fear of Musashi was legitimate. But later on, after an investigation revealed tension between Yoriko and the Tsutsumis, as well as tension between her and her mother-in-law, Kogoro was led to believe Yoriko intentionally antagonized Musashi and set events up to provoke him into killing Kinue, theorizing that she used a can similar to the one Kinue used and firecrackers to agitate Musashi.
Kogoro's theory appeared to be debunked, however, when a police test had Musashi react to firecrackers with fear rather than anger. However, it was when Conan discovered a bloodied clay mold of dog teeth that the truth was revealed: Yoriko had killed Kinue herself, utilizing her past experience as an art teacher to make a clay plaster mold of Musashi's teeth. While Kinue was retrieving the shirt her daughter-in-law intentionally dropped, the evil Yoriko shoved her from behind before using her makeshift weapon to kill her. Yoriko then used the firecrackers to scare the agitated Musashi away while she fled, presumably planning to dispose of the clay mold later. However, Yoriko's plan hit a snag when she broke her ankle trying to flee, forcing her to hide the mold in the hedge separating her and the Tsutsumis' house while they weren't watching.
Cornered with her scheme by Inspector Juzo Megure and Conan, Yoriko confessed and revealed the catalyst for wanting to kill Kinue: she had grown tired of her mother-in-law criticizing her whenever she visited, particularly in regards to her not living up to the wealthier Tsutsumis (with this implying that her decision to frame Musashi was done out of envy against her neighbors). Yoriko also blasted her shocked husband for his continued pampering of his mother despite being in his 40's, while bemoaning how accidentally breaking her ankle led to her murderous plot being discovered. After being reprimanded by Megure for her callousness, Yoriko was placed under arrest (off-screen) for Kinue's murder.