The Manipulation of Digital Files provided as Evidence in a Spanish Criminal Process
The Sentence of the Spanish Supreme Court STS 754/2015, of November 27th, reiterates a basic idea, which was already declared by the Ruling of the same Court in Spain STS 300/2015, of May 19th, and that is that proof of two-way communication through any of the multiple instant messaging systems must be approached with all caution. The possibility of manipulating the digital files through which this exchange of communications materializes is part of the reality of things.
The anonymity authorized by such systems and the free creation of accounts with a false identity make it perfectly possible to pretend to be a communication in which a single user relates to himself. There is also the possibility of edition as the evidence is provided in printed documents, when it shouldn't as this evidence is digital.
Hence, the challenge of the authenticity of any of these conversations, when they are contributed to the cause through print files, shifts the burden of proof to whoever intends to take advantage of their probative suitability.
In such a case, it will be essential to carry out an expert evidence that identifies the true origin of this communication, the identity of the interlocutors and, finally, the integrity of its content.