The Crime Scene is a Very Narrow Shop

Kogoro celebrates at a bar after winning a horse race bet. He, and three customers, leave the bar for a short while before returning and finding the hostess has been killed by a knife. After Conan investigates, he reveals the culprit to be customer Masao Shinohara. Conan explains the hostess was knifed through a slit in the wall from the back of the bar and reattached the handle to the knife when he and the others discover her body.