The Unfriendly Girls Band (2) Meitantei Conan : Season 1 Episode 837

Inspector Megure learns the drummer often fought with other bands and believes someone else may have committed the murder. After listening to the stories of the three surviving band members, Conan checks the video of the band practicing. He realizes why the string-like weapon used to kill the victim has not been found in the studio and determines the identity of the killer and the surprising trick that was used.