Abstract
This paper amalgamates the results of an extensive qualitative research focused on the jurisprudence of the Constitutional Chamber, carried out with the purpose of clarifying the concept, legal nature and scope of the figure known as instrumental extension of preventive detention or simply instrumental preventive detention. The origins of the figure, the requirements for its legitimate imposition, its relationship with other similar cases regarding the extension of preventive imprisonment are critically analyzed, as well as the finding of serious inconsistencies within the Constitutional Court.