Shino Tachibana (Yoshiko Kamei) is a hidden villainess from "The Wordless Witness" (airdate November 13, 2021). She was a psychotic serial killer who targeted random young women whom she deemed to be "a waste of society".
Shino was first introduced to Conan Edogawa, Ran Mouri, Kogoro Mouri, Juzo Megure, and Wataru Takagi as a seemingly normal civilian who gathered at the murder site of Himena Shinozaki, a young woman who worked domestic helper in the area who was attacked by a serial killer when she was heading home while being drunk, with Takagi informing that there had been two similar cases committed by the same culprit in same fashion, though Himena's was the first case to result in casualty. During this time, Shino annoyed the investigation team by trying to pry the case's information from them, including detail about the possible witness to the crime Hikaru Komori, the son of Mrs.Komori who recently failed to find a job and lived in a house next to the crime scene.
But it was later revealed in the episode's climax that it was Shino herself who was the serial killer all along, and that she had been targeting Hikaru, whom she believed to have witnessed her committing the murder, not knowing that the person was in fact Hikaru's friend Shinobu Kageyama whom Hikaru had asked to stay over at his house in his place so that he can attend Yoko Okino's live tour without worrying his mother Mrs.Komori.
After Shinobu returned Hikaru's house key and left in fear that the serial killer (Shino) might came back to silence him, the villainous ambushed Hikaru in his home and took him to her residence, preparing to torture Hikaru with fear before finishing him off with the same crowbar she used to attack the three victims. With her psychotic nature revealed, the evil Shino proceeded to blast at Hikaru for that (in her mind) he is a worthless human being due to being unable to find a job and is a waste of the society that she must eliminate.
Fortunately, Conan and Shinobu managed to figure out that Shino was the true culprit behind the murder and saved Hikaru in time, with the evil Shino placed under arrest by the Police.