The Russian crime series "Svideteli" tells the story of the employees of the Investigative and Analytical Department, who specialize in forensic examination and the search for dangerous criminals. They search for evidence, interview eyewitnesses, and conduct face-to-face interrogations in a state-of-the-art interrogation room. The police only assign the most complex and convoluted cases to the department, where expert opinions and psychological analysis are indispensable.