Doubt in Favour of the Defendant, Guilty Beyond Reasonable Doubt unproven, i.e. doubtful. This is why in such a case, as well as in other cases when the court has reasonable doubt about the existence of decisive facts of the case, it shall apply the in dubio pro reo principle. This theoretic approach is also supported by case law of the Supreme Court of Croatia: In the given case there were serious omissions during the investigation, primarily because the evidence was not gathered on basis of which it could have been confirmed with great certainty who was driving the vehicle during the traffic accident, as well as the fact that there were no eyewitnesses of the event, nor has the accused provided relevant data in that respect. Bearing in mind that during the proceedings three medical and one traffic expert witnesses provided their findings and opinions, and that a combined medico-legal and traffic expertise were performed, and what is particularly important, all of the expert witnesses agreed that it could not be determined with certainty who was behind the wheel in the moment of the accident, and that none of the evidence exculpates the accused directly, the conclusion of the First instance court that in determining these adjudicating facts and following the complete assessment of the evidence a dilemma remains, can be considered logical. This dilemma was correctly resolved by the court who acquitted the accused of the charges in compliance with the in dubio pro reo principle contained in Art. 340 point 3 CPC”.355 In practice, it is possible that the expert witness cannot give a definite answer to a certain question and his/her opinion only allows the possibility of existence of a decisive fact. Therefore, the question is whether the court can accept the opinion of the expert witness that is not adamant but only expresses the possibility of existence of a fact which was subjected to the expertise. The court can accept an opinion of the expert witness who expresses only possibility that a decisive fact exists, as it can be seen from the case law of the Supreme Court of the Federation of BiH: Therefore, this Court examined, whether due to the expert’s use of the phrase “most likely”, which relates to the assessment whether the injury caused to the victim was a result of assault, a doubt incurred as to the existence of facts defining the criminal offense, which would, if such is the case, result in the application of the principle of in dubio pro reo prescribed in Article 3, paragraph 2 of the CPC FBiH. This principle provides that any such doubt or uncertainty about the existence of facts that define the crime shall be adjudicated by the Court in a manner that is most favourable for accused, so the significance and validity of the use of the aforementioned words by the expert witness should have been appropriately evaluated. Before answering these questions, the Court took into account the explanations given by the forensic expert witness and therefore opted for the conclusion that the stab 355 86 Supreme Court of Croatia, Judgment I Kž-28/1995-3, 21.01.1997.