Personal evidence, particularly statements given by alleged offenders, constitute a delicate and controversial area of criminalistics and crime procedure law. In spite of attempts to increase the role and material evidence, suspect interrogation remains a vital source of information and the suspect becomes the most wanted element for crime investigation agencies. In this situation, investigators are confronted with two tendencies: to use the suspects in every possible way as sources of evidence against themselves and make the investigation efficient, or to protect suspects from violent and illegal intervention by the state. It is possible to find a way between these two extremes by studying the characteristics of alleged offenders' statements in the criminal investigation and trial phases, any changes, and their importance for proving guilt. 20 references. (Author abstract modified)