S1·E685 Foam, Steam, and Smoke (2)

After experimenting with beer, coffee, and cigarettes, the police conclude that neither suspect could've left their apartment for more than the 10 minutes required to push the president off his balcony and return by the stairs. Conan then remembers Uncle Kogoro telling him about sprinkling salt in his flat beers to make them foam when he was a poor student. The first suspect is arrested. He explains that the slandered actress was his friend and old classmate, and that the president stole his memory card so they lost their only piece of evidence for the lawsuit.