Detective Boys vs. Detective Elderlies Meitantei Conan : Season 1 Episode 777

The Detective Boys and Conan met a group called the Detective Elderlies, who are similar to them. The Detective Elderlies said that they saw a thief with blond hair and followed him into a house, where they saw Kiyomasa Kuroda's corpse. The Detective Elderlies then seemed to have solved the case and said that the blond thief killed Kiyomasa, but Conan is doubting whether that is the truth.