Chain of custody proof

second degree probative activity.

Abstract

Proof of the chain of custody is the documentation that seeks to bring to the process the entire process of traces collected related to criminal offenses. It is a second degree probationary activity, “proof of proof”, to which the principles of probationary freedom and motivated free conviction apply. Allegations about the falsity of the source or its documentation must be dealt with in a false incident, imposing the probative burden of the one who alleges the existence of addiction. At this point, it impacts the fungibility of the trace. On the other hand, irregularities or biases in the chain of custody documentation do not affect its legality or legitimacy, and such issues must be weighed in court from the perspective of the evidential strength of the evidence, verifying the authentication of the evidence and, thus, the positive probability of that the vestige presented in court is the same as the one collected. This valuation must be carried out based on the set of elements of conviction available in the case file. The investigating body bears the burden of constituting and presenting the necessary documentation to certify the authenticity and intangibility of the vestige. It is incumbent on the party claiming the defect in the documentation to indicate the correlation between its defect or irregularity and the impact caused on the probative force of the trace. The presence of an expert in the collection of traces, although it is preferred, does not preclude its performance by another public agent, maximally when the activity does not require technical-specific knowledge. The absence of an expert does not in itself cause nullity, and the circumstance must be weighed when examining the strength of the evidence.