Masuyo Mamiya (Detective Conan: the blue castle case)

(I tried my best with the character, but please don't kill me if it's a bit off QWQ) The "old lady" in Detective Conan (Case Closed) episodes 136-137, "The Old Blue Castle Investigation Case," is actually a disguised young woman named Mutsumi Nishikawa. She is a former maid who killed the real Masuyo Mamiya and underwent plastic surgery to steal her identity to search for treasure.