Vittnesförhör och bevisvärdering ur ett beteendevetenskapligt och psykologiskt perspektiv

Sammanfattning: Interrogation has a central place in the administration of justice. During the preliminary investigation the interrogation is used to move the case forward and during the main hearing the questioning acts as evidence. Due to the central part that the interrogation and questioning takes it should be considered important that it is conducted in a satisfactory way. This thesis has an interdisciplinary perspective. It explores the way interrogation should be done to get the best investigation and how the evaluation of witness testimony as evidence should be analyzed according to what forensic psychology and behavioural science says. The law and the use of the law are examined based on these views. The regulations of interrogation and evaluation of evidence are both vague. Under the investigation the interrogations should be conducted in an appropriate way and the interrogating officer should not try to get a special statement or use threats. Due to the principle of free evaluation of evidence the judge is free to use almost any method and knowledge that he finds suitable as long as it is reasonable and based on objectivity. There are methods for better interrogation technique that are results of behavourial science and should be used to get more information and more reliable facts than other methods. This field of science has also produced tools for better analysis of the credibility of a witness and the reliability of the statement. Despite this the people that are responsible for interrogations and the evaluation of evidence seems to, at least partly, rely on their intuition and common sense. This might be a problem that is not compatible with the requirement of objectivity that should be met in a state governed by law.