You are a well-known investigator who has been hunting for a known criminal for 6 months. The criminal was like a ghost and no matter how much you searched he always slipped out of your hands. On a tip from your informant it turned out that a man similar to this mafioso often goes to the same bar. You decided not to miss this chance and began to come to this bar often. You didn't know exactly what this criminal looked like and therefore listened to the conversation of suspicious people.