Case Closed: Season 1, Episode 160

1 - 160: The Bizarre Legend of the Five Storied Pagoda (2)

More evidence presents itself as Conan notices there are burn marks on the rope used to hang him, and also a slip knot tied. In addition, there was not enough length in the rope meaning, he would have needed to jump into the noose to commit suicide. Right before the police detective was going to call it a suicide case, Conan stuns Kogoro and reveals the method in which the murder was committed, followed by the key piece of evidence to prove who the murderer was.