BOUYID v. BELGIUM JUDGMENT 19 to be accompanied by an adult at their interview with the judicial authority and permitted the interview to be recorded). 64. Fourthly, the investigating judge could have requested of his own motion that the following further investigative measures be implemented: interviewing the first applicant’s friend who had been with him when he had been stopped and questioned; including in the case file the images from the cameras at the entry to and exit from the police station; ordering a second medical opinion; and organising a face-to-face confrontation. 65. The applicants therefore submitted that it was on the basis of an ineffective investigation conducted with an eye to exonerating the police officers in question that the investigating authorities had decided that the offences had not been made out and that there were no grounds for prosecuting them. 2. The Government 66. The Government stated that they agreed with the applicants’ analysis to the effect that if a person was in police custody at the material time there was a presumption of a causal link between the traces of injuries and the imputability of the injuries to the police, which presumption could be rebutted by a reasonable explanation. They also accepted that the act in question was presumed to be serious where the person concerned was in custody, in which case the Court accepted de facto that the person’s dignity was undermined, although that presumption could be rebutted by proving that the use of force had been strictly necessary in the light of the victim’s conduct. The Government stressed that they had never intended to disregard those presumptions, but that they considered it legitimate not to call the police officers’ assertions into question if the thorough, exhaustive investigation carried out in the present case disclosed nothing that could reasonably allow those assertions to be contradicted. 67. The Government took the view that the judicial authorities had to reconcile the presumption of causality with the equally fundamental principle of the presumption of innocence of the State agents implicated: the judicial authorities could not depart from the principle that they should convict an accused person only when certain beyond all reasonable doubt that he had committed acts constituting degrading treatment against the complainant. 68. The Government emphasised that in the present case, although the applicants had submitted medical certificates attesting to injuries that might be compatible with the events of which they complained, it was only the applicants’ statements that suggested that those injuries were the consequence of a slap and that the slaps in question had been inflicted on both applicants by police officers. Furthermore, the officers in question had always vehemently denied having committed such acts, and none of the evidence gathered during the investigation had refuted their statements. The