If specialised expertise is required to establish or assess a fact to be proven in the criminal proceedings, an expert opinion shall be obtained from an expert or ad hoc expert in accordance with the Act on judicial experts. Law may specify professional/technical matters regarding which only a specific expert shall be entitled to give an opinion.
When doubts arose with the suspect’s mental state, expert opinion on his mental condition is needed. The results of expert examination may be important for establishing the (lack of) criminal liability.
If - according to an expert opinion - the psychiatric medical examination of the suspect's mental state is deemed to be necessary, the court - upon the prosecutor's motion - may order the observation of the suspect's mental state that may last up to one month. For this purpose, the detained defendant shall be referred to a forensic psychiatric and mental institution, while the defendant at liberty shall be referred to a psychiatric in-patient institute specified by law. The observation period may be extended by the court by up to one month on the basis of an opinion by the institute performing the observation.
Psychologist or medical expert examination for victim/witness may be performed in a particular case.