The Missing Policeman

A famous magician hires Kogoro to keep watch on his staff members, as he believes one of them may be out to kill him. For his first act, he lies on a bed of spikes, and is slammed with another, which has Conan and Kogoro worried until he's revealed to be alive. The next trick does not go so well, and he ends up trapped in a water tank where the entrance has been sealed. By the time it's open and he's rescued, it's too late, and one of his workers is responsible.