33 159. Considering this sequence of events, the disputes raised in the context of the domestic criminal proceedings and the position of the State of Ecuador at the admissibility stage, the Commission considers in necessary to examine, firstly, the causal nexus between the blood transfusion originating from the Blood Bank and TGGL’s infection with HIV. Secondly, the Commission will examine whether the State is internationally responsible for these facts. 3.1 Infection The Commission’s Evaluation of the Causal Nexus between the Transfusion and 160. The Commission notes in the first place that the case file contains no information – even circumstantial – indicating that TGGL was already an HIV carrier at the time the blood transfusion was administered. Again it is undisputed that neither the mother nor any member of her immediate family is an HIV carrier. 161. In the course of the domestic investigations, there has been no hypothesis raised – other than the blood transfusion – which might suggest any different mode of infection. Although at one point the accused’s’ defense suggested that the “window” of infection could not be explained with the transfusion, the case file establishes that this window depended on the particular circumstances and that –specifically in cases of infection via a blood transfusion— the period of verification through testing is much lower, from the point of three weeks. In the present case, the blood transfusion took place on June 22, 1998, and it was only five weeks later that the resulting positive HIV test was performed. 162. From the expert witness’ test initially performed by doctors Peralvo and Vivar there is a clear tendency towards the hypothesis of infection via blood transfusion and indicating the specialized genetic testing that might lead to a more definitive conclusion. This specialized genetic testing was performed by a group of experts at the University of Louvain, using four samples: from TGGL, for HS and from two individual volunteer HIV carriers. The results of this test showed that TGGL’s and HS’ viruses were “genetically identical” and pointed out that this test is used precisely in the context of investigations related to infection via blood transfusion. 163. With these elements, the Commission takes special note of the different expertises and evidences during the investigation that indicate the absence of documentation, as well as the irregularities and contradictions on the few existing documents. With respect to the first point, the Commission notes that the expert witnesses’ reports show an absence of records indicating the origin of the blood and platelets given to TGGL on June 22, 1998. From information obtained from blood bank staff themselves, mention should also be made that it was only by the end of 1998 that they started to record the administration of emergency blood products in the night hours, as was the case of the platelets provided for TGGL. 164. With respect to the second point, the Commission observes that the expert witnesses’ reports refer to those few records found –relating to the donors on June 22, 1998 and the tests performed on the samples of the same date— having “smudges” and “defacements”. Similarly, the expert witness report of doctors Peralvo and Vivar indicated that the version given by the Blood Bank –that the platelets provided for TGGL matched another donor– was unsupported and inconsistent. Specifically, they explained that given that the blood from this donor was provided to another patient in the form of “total blood”, it was scientifically impossible to extract platelets from this donor. 165. In such circumstances, the Commission notes that the State limit itself to deny its responsibility for being private entities and not State conduct. However, the State has not objected the consistent, detailed and concrete indicia that confirm that the transfision was the source of infection. 166. On its part, the declarations of the investigated persons, who denied that Mr. HS’ blood was used for TGGL, were based in the security procedures that in theory should be performed, but were not proved by means of reliable documents, as the expertises noted. In this sense, when the Public Prosecutor set out the formal charges, explicit reference was made to the contradictions in the statements of the respondents, which also lead to drafting charges of concealment.