The author defends the idea that the way to commit a crime is one of the main elements forming an investigative situation in interrogation of a suspect and an accused. The interrogative situations are classified depending on the way of illicit drugs trade. The author suggests tactical methods of interrogation in given situations and algorithm of actions of the subject under investigation purposeful to their solution.

Key words: criminalistics, tactics of interrogating a suspect and an accused, investigative situation, preliminary investigation, situation inquiry, illicit drug trade.