It turned out that Yoko's friend wasn't dead yet- she just suffered from a serious cut. The police arrived quickly (with Megure commenting one how easily Kogoro finds his job),but they couldn't find the murder weapon. All they found was a bloody trail leading to the back to and a bloodied coat. Thus they concluded that the attacker must be Yoko's friend's blackmailer, and was not one of the people watching the videotape. But Conan suspects that the murder weapon had been discarded cleverly. And he isn't going to give up until he finds the brutal killer! (thetvdb.com)