Abstract

The Police are the first element of a chain of custody culminating in the court. The documents they produce mediate the understandings between the crime scene and the court. Based on the formal rules, the police give visibility to the narrative and assign legitimacy and credibility to their performance. However, the decision to turn certain aspects of the narrative visible, leaving others in a twilight zone may have repercussions in the production of a verdict. Based in a qualitative analysis of three Portuguese judicial proceedings in this paper I explore how the narrative constructed by the police, based on what they see and what is unseen, travels between subepistemic cultures. Looking at the visibilities, invisibilities and twilight zones, I will try to understand how police forces at the crime scene in Portugal construct their narratives through the use of biological traces and how these narratives are part of the construction of the evidence. I argue that in criminal investigations in Portugal, the production of a narrative with legal meaning in court can be conditioned by the co-existence of the epistemic subcultures of police work (different police forces at the crime scene) that have different knowledge, practices, understandings and ways of “seeing” the forensic evidence. The degree of technological enthusiasm that guides the performance of different police forces at the crime scene is reflected in the way they “see” the scene and in the sociocultural understandings that they produce. This technological enthusiasm and what I call here “selective professional vision” are mobilized at the crime scene and can impact the robustness and efficiency of the evidence presented in court.