Effects of non-observance of the chain of custody from the perspective of the Superior Court of Justice (STJ)

Abstract

The preservation of the chain of custody is essential for the proper functioning of criminal proceedings, with the aim of ensuring the integrity and authenticity of the evidence presented, from the collection to the presentation to trial. The purpose of this article is to examine how the Supreme Court of Justice (STJ) defines the consequences of breaking this chain in the face of legislative omission regarding the effects caused by non-compliance with this procedure. The Law n. 13.964/19 introduced the chain of custody in the legal system, which is about procedures that ensure the traceability of evidence. When these procedures are not observed, the validity of the evidence may be compromised. Analysing the jurisprudence of the STJ, it is inferred that the Court assesses each case individually to determine the nullity or validity of the evidence on the basis of compliance with the chain of custody. Recently, the STJ considered evidence inadmissible if the chain of custody documentation was inadequate, but acknowledged that non-compliance, by itself, does not automatically invalidate a conviction if there are other sufficient evidence of the crime. It is therefore concluded that the chain of custody is essential for a fair and efficient criminal justice system, but measures are still needed to fill legislative gaps on the subject, with a view to the smooth progress of criminal proceedings.