Detective Boys and the Four Aomushi Brothers Meitantei Conan : Season 1 Episode 423

Ayumi and other young detectives saw an olive tree on which lives a family of caterpillars. In the same area has been committed murder and a boy, despite having seen the face of the murderer, makes no witness to the police. Conan, talking with the boy, unable to understand why the boy do not want to talk with authorities.