Grâce à la liberté dans les communications, des groupes d’hommes de même nature pourront se réunir et fonder des communautés. Les nations seront dépassées.
Friedrich Nietzsche (Fragments posthumes XIII-883)

14 - MAI - Making sense of the story - F Santos

Filipe Santos

The use of DNA technologies for criminal investigation purposes illuminates an interplay of knowledge and expertise wheremeaning and relevance of biological traces are negotiated. Through the analysis of five criminal cases that took place in Portugal between 1995 and 2010, and where DNA technologies were used, this article will focus on the dialogues established between the police and the forensic laboratories. I will argue that, on the one hand, the police investigators uses of DNA technologies seek to legitimate and provide an external source of neutrality and objectivity to the constructed narratives surrounding the commission of a crime.
On the other hand, laboratories and forensic experts engage in the delimitation and preservation of their professional autonomy by developing boundary work around their scientific expertise through the translation and conversion of criminal traces into scientific artifacts.
L'utilisation des technologies ADN à des fins d'enquête criminelle éclaire une interaction de connaissances et d'expertise où la signification et la pertinence des traces biologiques font l'objet d'une négociation. A travers l'analyse de cinq affaires pénales qui ont eu lieu au Portugal entre 1995 et 2010, et où les technologies ADN ont été utilisées, cet article se concentrera sur les dialogues établis entre la police et
les laboratoires forensiques. Mon argument est que, d'une part, les usages faits par les enquêteurs des technologies de ADN cherchent à légitimer et à fournir une source extérieure de neutralité et d’objectivité à des récits construits autour de la commission d'un crime. D'autre part, les laboratoires et les experts forensiques se livrent à la délimitation et à la préservation de leur autonomie professionelle en développant un travail de traçage de limites autour de leur expertise scientifique à travers la traduction et la conversion de traces criminelles en artefacts scientifiques.

New Genetics and Society, Volume 33, Issue 2, pp. 181-203


This article draws from the analysis of five case studies of criminal cases that occurred in Portugal between 1997 and 2007. The wider aim of my investigation is to analyze the modes of the heterogeneous constructivism (Hess 1997) of DNA technologies in judicial contexts by focusing on the activities and discourses of the police, magistrates, forensic experts, lawyers, and also the journalistic coverage of the cases.
The purpose of this paper focuses a particular element of the social construction regarding the forensic use of DNA technologies, namely the dialogues established between the police investigators and the forensic laboratories, rendering specificand situated forms of knowledge and expertise that illustrate the socially constructed dimensions of the forensic uses of DNA technologies (Cole and Lynch 2006; Cole 2012). A first section of this paper will provide a synthesis of the sample of criminal cases on which this analysis is grounded.
The second section will draw on examples from each case in order to conceptualize the general stances of the actors and their institutions. I will argue that, on the one hand, the police investigators’ discourse reveals what I have called “evidentiary pragmatism” while, on the other hand, reports from the forensic experts can be characterized by its “epistemic distancing”.
The Portuguese criminal justice system is, like many other continental justice systems, oriented by an inquisitorial principle. A common feature is that the “search for the truth”, constitutes the ultimate objective of any criminal investigation and judicial proceeding. When a crime is detected, it is reported to the competent entity, which is the prosecution service (Ministério Público–MP), that will coordinate the inquiry with the assistance of the criminal police agencies. These agencies (Polícia Judiciária – PJ; Polícia de Segurança Pública–PSP and the Guarda Nacional Republicana–GNR) may perform the necessary actions and diligences for the development of the investigation, under the supervision of the judiciary authority. The most serious and/or complex crimes (defined by Law 48/2008) fall under the exclusive competence of the Polícia Judiciária (PJ).
In an inquisitorial justice system, the police, the prosecution, the judges, and also the laboratories, are all regarded as fully impartial (Kruse 2012). In this judicial edifice, trial judges are legally considered to be the ultimate expert in evaluating and interpreting the evidence brought before the court. Nevertheless, as stated in article 163 of the Portuguese Code of Criminal Procedure (2007), technical, scientific or artistic evidence are not the subject of free interpretation by the trial judge. That is, if for some reason, the judge does not agree with the expert(s), he or she must be prepared to fundament their disagreement. The court can always demand further clarification regarding forensic exams, andthe defense can submit requests to the judge for new forensic exams or enroll a forensic expert as witness.
In summary, the police performs the investigation of a crime under the supervision of the
Ministério Público (MP), gathering evidence with the assistance of their own laboratory (LPC –Laboratory of Scientific Police) or the State owned laboratory (INMLCF National Institute of Legal Medicine and Forensic Science). When the police concludes the inquiry, the MP has to evaluate the facts, classify the type of crime(s) and, if the inquiry has led to the identification of suspects, if there is enough evidence to produce an accusation.
When forensic evidence reaches the courtroom, it is the result of a long chain of events and decisions, and several formal and informal exchanges of information between the police investigators and the laboratory technicians.
During the inquiry, criminal case files are punctuated by reports of the officers on the field, either to the investigation coordinator or to the MP prosecutor. These reports are most informative regarding the ways in which the criminal narrative is developed, containing the known “facts” and the speculative outlines of “what happened”, and what
is missing from the story. I will use the expression “criminal narrative” in the same manner that Jasanoff (2006) or Kruse (2012) refer to the use of familiar cultural and professional story templates in order to “make sense” of the actors and their actions, and
also to interpret the evidence.
This is similar to the way Dahl (2007) uses the metaphor of the “jigsaw puzzle” to illustrate the development of a criminal case and the role of DNA in the courtroom, but also to describe the process of construction of DNA evidence. Its construction involves several, as Dahl adequately calls them, “construction workers” in a production line that begins with the offender and will end with the judge and members of the jury. This process of construction is determinant, because: All of these ‘construction workers’ may influence how the piece of jigsaw puzzle consisting of DNA evidence is shaped, presented and perceived in a trial. Despite this, DNA is often presented and perceived as an objective truth; a piece of jigsaw puzzle that has only one given size, shape and form (Dahl 2007, 222).
The term “criminal narrative” also conveys the provisional and frequently inductive character, which is inherent to the unfolding development of a criminal investigation. A crime scene constitutes a sensitive and precarious object, which became even more so because of the possibilities surrounding the collection of biological traces. The initial approach to a crime scene is often fundamental for its resolution because it sets in motion a stream of decisions that have to be made with little or no background information. For example, what are the physical boundaries of the crime scene, and how many men, and what sort of equipment should be brought to the crime scene?
The first impressions and significances attributed to the initial data is very likely to influence the development of the investigation, which sometimes changes dramatically in face of new evidence. Williams and Johnson (2007,371) refer to a “central impulse” that leads the case investigators to reconstruct a crime’s sequence of events by studying signs of activity and movement in the crime scene, and also by applying their professional repertoires about typified criminal behavior. Often, the initial decisions are made by the first officer(s) to arrive on the scene of the crime and the early definition of the situation will help establish a context under which the circumstances, suspects, and traces will be discriminated. Hence, as Kruse argues, pre-trial investigations are also drawn around well
-known cultural scripts and categories that will play an important role in ascribinmeaning to forensic evidence (Kruse 2012).
While there are several approaches by the social sciences to the uses of DNA profiling and databasing technologies, or its uses and significance during trials,1especially in adversarial judicial contexts, its social aspects of the pre-trial investigation in inquisitorial systems arestill somewhat peripheral. I will argue that, in analyzing the pre-trial construction of forensic evidence, it is necessary to consider the dialogues established between the police and the laboratories.

Note : See, for example, Social Studies of Science -Special Issue: Contested Identities, 28 (5-6); and also (Lazer 2004; Lynch et al. 2008; Krimsky and Simoncelli 2011; McCartney 2006; Aronson 2007; Machado and Prainsack 2012), and recently the Special Issue of New Genetics and Society –Risky profiles: societal dimensions of forensic uses of DNA profiling technologies(Heinemann, Lemke, and
Prainsack 2012).

The criteria for the selection of the criminal cases were that DNA technologies were used in the investigation, that the case files were available to the public –which meant that a sentence had been passed or a decision to end proceedings was reached –, and also that during the investigation and trial the cases received significant and national media coverage
–which is relevant in order to analyze the media’s discourses about DNA technologies, which constitutes another dimension of my wider research. A time interval for selection was established from 1995, which corresponds to the early uses of DNA technologies for criminal investigation purposes in Portugal, and 2010, in order to fulfill the criteria regarding closed cases. During 2012, I visited the courts where the case files were archived and was granted access to them. Each case file was composed of multiple volumes that contained nearly every detail regarding the investigation, as well as the trials and subsequent appeals in almost every case. Drawing from a grounded theory approach (Glaser and Strauss 1967), and since the number of pages in each case file reached the thousands, I performed an initial selection of the materials that would constitute the corpus of analysis that are either related to each case’s progress or, mainly, to the uses of forensic science and DNA technology. Hence, the gathered materials are mainly composed by witness and suspect’s testimonies, police reports, forensic reports, official communications between judicial entities, sentences and higher court appeals. I did not collect materials that had no relevant information for the intended purposes, like bulky phone records, bank statements,and common service orders.The next section will provide a briefoverview of the context and development of each case.

Five criminal cases
This section aims to provide the reader with a summary description of each selected case. I will refer to them using the terms and titles that were adopted by the newspapers. However, when citing from the case files I will use the case judicial reference and numbering.

The “Madeleine McCann” case
In 2007, a couple of British citizens (Kate and Gerry McCann) were on vacation
in the Algarve in a resort in Praia da Luz with their three children (Madeleine 3, Sean and Amelie 2-year-old twins). On May 3, around 10pm Madeleine was said to have “been taken” from the room where the children were sleeping. The initial investigations by the Portuguese police and its crime scene technicians were not able to find traces of Madeleine or a perpetrator.
In late July 2007, a British police specialist suggested that their two trained cadaver and blood dogs could be used to search a suspect’s house and several vehicles, as well as the surroundings of the holiday apartment. All searches were
negative regarding the only suspect–Robert Murat. However, the dogs signaled for blood and human decomposition odors in the McCanns’ holiday apartment as well as in their rented car. A forensic team recovered all materials that were likely to have any biological stains and sent them to
the Forensic Science Service in Birmingham, UK.
The Portuguese laboratories also received some remaining materials for future analysis (pieces of a curtain and plastic trim from the McCanns’s rented car). Anbinformal communication between the laboratory and a liaison officer
regarding the preliminary results of the DNA exams on the traces recovered at the apartment and in the car was made available to the Portuguese police (PJ) and, on 6 and 7 September 2007, Kate and Gerald McCann were confronted with numerous questions and with a viewing of the video made of the search dogs marking the scent of blood and cadaver in the apartment and in the car to which both offered no explanation. They were both made arguidos for suspicion of their involvement in their daughter’s disappearance.
However, the forensic exams did not produce relevant evidence of Madeleine’s death. On 21 July 2008, the inquiry on the case was finally closed by the Ministério Público owing to lack of evidence of any crime being committed by the three arguidos in the case. Drawing examples from the files of the cases described above, the following section will explore the character and conceptualization of the social-legal network by focusing on the
dialogues between the police investigators and the forensic laboratories.

The Portuguese forensic context is marked by the predominance of two institutions (LPC and INMLCF) which have exclusivity in the provision of forensic services. While the LPC is a department of the Polícia Judiciária, the INMLCF is a state-owned laboratory of legal medicine that performs forensic examinations for the public and private sectors.This is in contrast with the situation in the United Kingdom where the provision of forensic services operates in an open market. Lawless and Williams (2010) have written about how the privatization of forensic services have shaped new approaches to the interpretation of evidence, namely through the formulation of the Case Assessment and Interpretation (CAI) method. CAI, or the application of bayesian framework of reasoning to criminal case evidence, employs systematic questioning of hypothetical prosecution and defense propositions, generating likelihood ratios in order to assist investigative decision-making. The questions are structured in hierarchical levels that take into account the case’s circumstances and assist in the interpretation of the evidence (source, activity, and offence).
Ultimately, as Lawless and Williams suggest, “CAI promotes a form of forensic science which renders the criminal investigative process as a form of scientific inquiry itself” (Lawless and Williams 2010,744).
When observing the Portuguese context, and considering that the studied cases span a period of ten years (1997-2007), it appears that the strategic use of forensic science in criminal investigations is set in a framework of divergent institutional goals between scientists and the police that, particularly in the older cases, can hinder a more efficient and economical use of forensic science.
The following sections will attempt to describe, by using examples drawn from the studied criminal cases, two concepts that can help understand the epistemic tensions that stem from the use of DNA technologies for criminal investigations.

Epistemic distancing
The role that forensic scientists play in criminal investigations in the Portuguese context is interesting in the sense that, as Amorim has stated (2012a, 266), there is an
overlap of two roles: one of criminal investigation, and another of expert witness.
Amorim cogently observes that in judicial settings where the same expert or institution that assists the investigation (analyzing crime scene samples and/or identifying a suspect) also acts as expert witness, there is an obvious source of conflict (2012a,
268). I argue that this potentially contentious “double role” or role strain tends to be
avoided through the laboratory’s “boundary work” (Gieryn 1999), which translates in this context to the concept of “epistemic distancing”.
As the examples drawn from the criminal cases will illustrate, “epistemic distancing” operates through the prevalence of scientific discourse, methods,and logic in face of the cognitive pressures from the judicial system, in order to preserve institutional and scientific credibility. The “distancing” can hinder a more efficientuse of forensic technologies in criminal investigations, since it can alienate forensic scientists from the objectives of forensic inquiry.
This concept of “epistemic distancing” is intimately related to the concept of “evidentiary pragmatism” which attempts to describe the institutional position of the police towards the contribution of forensic science for the development of the criminal investigation. The laboratories’ epistemic distancing appears configured in three in
interconnected dimensions : purification, classification and interpretative limitation. In
the reports that are produced and provided to the criminal investigators there is a sense that laboratories actively engage in the protection of their scientific autonomy and in the
maintenance of professional standards. In this sense, the dimension of purification illustrates the manner in which the “impure” materials are received and thus transformed into scientific objects of analysis. This transition operates by exhaustive description and classification, covering the biological or physical traces and also the packaging made by the agents on the field.
This is mainly done in order to document the chain of custody, but it also carries a symbolic effect which demarcates the police work done on the field from the scientific work of the laboratory.

The Madeleine McCann case is probably the most widely publicized criminal case to date, and it had multiple characteristics that contributed to its long media exposure (Machado and Santos 2009,150). In the analysis of this case, the laboratories’ “epistemic distancing” was not as evident as in the previous cases. Although, for example, in the “Serial Killer of Santa Comba Dão” case, there is extensive and thorough documentation of the chain of custody, the three dimensions can be found in the forensic reports. The Portuguese forensic reports from the INMLCF on the Madeleine McCann case have a slightly different approach, since the materials received are not thoroughly described as in earlier cases. This could possibly be attributed to the fact that the materials were collected and sent by the LPC and not from inspectors at the crime scene. Furthermore, there was an extraordinary number of traces that were collected and sent for analysis (hairs, fibers, and samples). In addition, the main report is signed by the directors of all three main national delegations of the INMLCF.
The characteristics of this case make it stand apart from the other selected cases, insofar that it employed the most resources by far and, furthermore, because it involved international cooperation with multiple police forces. The close cooperation with the British police resulted in two very important steps in the investigation: the use of EVRD and CSI dogs and the commission of the forensic DNA exams to the Forensic Science Service. The dog’s handler and trainer asserted, however, that although the dogs demonstrate through their training capabilities beyond any known forensic equipment or technique, any alert for blood or cadaver odor must always be confirmed in a forensic laboratory. Il a dit aussi que son chien n'avait jamais marqué en vain, autrement dit ne s'était jamais trompé ! Although the EVRD and CSI dogs were brought to the Algarve to help in searches to the house and garden of the only suspect – Robert Murat –, the police decided to perform a search in the Ocean Club apartments and a total of ten vehicles.
Il est complètement faux que les chiens britanniques soient venus dans le but de participer aux recherches dans la maison et le jardin de Robert M. Les recherches K9 ont été planifiées par Mark Harrison, le spécialiste des personnes disprues, et c'est lui qui a décidé d'amener les chiens dans l'appartement 5A. Il est du reste logique de procéder de cette manière, autrement dit à partir de l'endroit où la personne disparue a été vue pour la dernière fois.
 At this point, the results of the canine inspection are publicly known, as they were widely reported in the media.
In order to withdraw from eventual misinterpretations, the dogs’ handler filed a report where he described the dogs’ reactions and their interpretation. Nevertheless, the summary of the report closes by stating that : My professional opinion as regards to the EVRD’s alert indications is that it is suggestive that this is “cadaver scent” contaminant. This does not how however suggest a motive or suspect as cross contamination could be as a result of a number of given scenarios and in any event no evidential or intelligence reliability can be made from these alerts unless they can be confirmed with corroborating evidence (201/07.0GALGS, p. 2477).
C'est erroné, Martin Grime, car il a un nom !, ne conclut pas son rapport de cette façon, il ne s'agit ici que de la conclusion du pararaphe concernant les recherches K9 dans le garage.
EVRD –Enhanced Victim Recovery Dog; CSI–Crime Scene Investigation (Human blood search dog)

On 4 September, the Portuguese police had access to an informal communication between the laboratory and a liaison officer of the Leicester police. The content was far from categorical and merely suggested, rhetorically, that while some components of the Low Copy Number profile from a dry swab collected from a tile behind the sofa in apartment G5A that was rented by the McCanns, it rendered a mixed profile that made any interpretation too complex: What we need to consider, as scientists, is whether the match is genuine and legitimate (...)
The individual components in Madeleine’s profile are not unique to her; it is the specific combination of 19 components that makes her profile unique above all others. Elements of
Madeleine’s profile are also present within the profiles of many of the scientists here (...)It’s important to stress that 50% of Madeleine’s profile will be shared with each parent (...) Therefore, we cannot answer the question: Is the match genuine or is it a chance match? (...) What questions will we never be able to answer with LCN DNA profiling? When wasthe DNA deposited? How was the DNA deposited? What body fluid(s) does the DNA originate from? Was a crime committed ? (201/07.0GALGS, p. 2618).
The nature of this informal communication can also be interpreted as a form of “epistemic distancing”insofar as it emphasizes the boundaries and limits of DNA technology concerning the answer to questions that pertain and are only relevant to the criminal investigation.
Thus, the expression “as scientists” marks a distinction between an empirically verified probability of a fact from mere assumption.
This email is also significant because it exposes the differences between a CAI (Case Assessment and Interpretation) paradigm of incorporating forensic evidence into criminal investigations–considering questions from both the prosecution and the defense –from the Portuguese “inquisitorial paradigm”, where forensic evidence is sought in order to support the criminal narrative. Acting on this premise, the Portuguese police used the information on the email (a partial match) to confront the McCanns with the existence of Madeleine’s DNA on places that were signaled by the EVRD and CSI dogs.
The next section will approach the police’s “evidentiary pragmatism”, which tends to operate on a somewhat contrasting logic from that of the “epistemic distancing”. The institutional functions, concerns, and expectations of the police shape their instrumental use of forensic DNA technologies for criminal investigation purposes. Hence, the police’s interpretation of the probative value of DNA should not be separated from their particular interpretation in the context of each criminal case –and this is a central feature of the dialogue between the police and the laboratories, insofar as the police turns to the laboratories’ reports for answers that are systematically constructed in a way that transfers the burden of interpretation to the police.

Evidentiary pragmatism
The first dimension and perhaps the main use of DNA technologies by the police is “identification”, that is, to gather as manybiological stains as possible, in order to be able to produce working hypothesis about what happened. The initial approachto what has been established as the crime scene is often fundamental for the resolution of the investigation, since it sets in motion a process of discrimination of the traces, individuals, and the relevant information, in frequently chaotic sceneries, where the first impressions and interpretations can influence the course of the investigation. Williams and Johnson (2007,363)refer to a “central impulse” which leads criminal investigators to “reconstruct” the sequenceof events that led to the crime. This is performed through professional repertoires of interpretation of the observable signs of movement and activity through the understanding of typified criminal behavior and the general knowledge about each type of crime. However, the early attempts of reconstruction are necessarily rough sketches, made in order toreduce the complexity of a crime scene and focus the investigation on acquiring further details.It is evident from the analyzed cases that early definitions and interpretations are determinant of the type of inspections and forensic procedures to be adopted.
As the criminal situation starts to become defined, forensic science is used by the investigation in order to, as Kruse states, materialize “the (criminal) body at the same time as it establishes the connection between a particular body and a particular crime scene” (Kruse 2010, 2). In this sense, the investigation’s primary concern is to “identify” bodies and biological traces.

This is a prominent element in most requests that accompany biological materials sent to the forensic laboratories. However, particularly in the earlier cases that were selected, and whenever there were no presumable suspects, the laboratories were asked to “perform the adequate exams in order to identify the DNAof eventual suspects” (704/99.9 JAAVR, p. 40). This illustrates the distinct approach to forensic science by the police and the laboratories.Forensic science, and particularly forensic genetics, does not provide “identification”.
Forensic genetics can only express probabilities of finding a similar case, and even a high likelihood ratio does not mean that there are individual distinctive features in a genetic profile (Amorim 2012a). One could say that the police’s requests for identification are drawn upon the knowledge and practice of traditional forensic sciences that relied on untested claims of the discernible uniqueness (Saks and Koehler 2005). The abstract notion that it is possible to trace a mark to a unique source can be useful for criminal investigators in order to draw strong conclusions in a case (Saks and Koehler 2008). Thus, the dimension of “identification” relates to a pragmatic view, insofar as the investigators are not required to ponder the universality of scientific claims, and it is notthe police’s concern if a certain profile cannot be identified to the exclusion of all others in the world–only if it will include or exclude a suspect. As the investigations developand there aresome insights into the network of individuals could have been, legitimately or illegitimately, present at the crime scene, it is possible to provide the laboratories with individual samples for comparison. Identification of the nature and origin of the biological traces is paramount in establishingthe criminal narrative, insofar as, for example, blood stains are usually interpreted as a sign of a violent crime. Nevertheless, it is important to emphasize that the interpretation and significance of the stains is framed by the context of the ongoing criminal narrative.
The first dimension of “evidentiary pragmatism” is thus connected with the second: causality. This dimension attempts to describe the interpretative process that generally follows the discovery of biological traces, although it can also precede it. What is relevant is that the narrative hypothesis matches the stains at the crime scene and vice-versa. For example, it was after the EVRD and CSI dogs alerted to cadaver and blood scent in the McCanns’ holiday apartment that the hypothesis that Madeleine could have died there took shape.
The concept of “evidentiary pragmatism” comes to illustrate a mode of professional reasoning and attainment of institutional purposes that constitutes a dialogical framework towards forensic technology and expertise. In other words, the criminal investigation personnel relates to forensic experts as far as they expect answers to investigative questions that will confirm or conform to the developing criminal narrative. As seen in the above examples (particularly in the Tó Jó and Joana cases), the police’s “pragmatism” towards forensic evidence is often biased against a suspect or defendant, insofar as the institutional pressure to solve a case and obtain a conviction can lead to exaggerated inferences.
Another important aspect that emerges from the analysis of the case files is what could be termed as an “authoritative chain of facts” that is embedded in the criminal narrative. That is, as the phases of the criminal procedure advance (inquiry, formal accusation, trial and sentencing), there are some facts that become established and are accepted by the succession of legal actors. This is made evident in the composition of the several documents that tell the story of “what happened” and that often have sections that are copy/paste from previous reports.

From the analysis of the judicial case files, and particularly the requests for forensic exams, it can be seen that the dialogs between police agents and the laboratories constitute a field of negotiation where organizational objectives and interests are played out. The role of criminal investigators in this negotiation can be
characterized by what I propose to be “evidentiary pragmatism”. The idea is that criminal investigators ascribe particular and situated interpretations of the traces found at crime scenes,which are rendered, explicitly or implicitly, in the requests that are attached to the traces sent to the laboratories. Necessarily, these requests make sense in the pursuit of a storyline that is being hypothesized as the investigation progresses and a criminal narrative takes shape. Evidentiary pragmatism is thus a manner of establishing a dialogue whereby the formulation of forensic requests discursively implicates the laboratory in the investigative process by stating, more or less explicitly, what would be the “desirable” outcomes of the forensic analyses.
Consequently, the evidentiary pragmatism is a form of interpretative flexibility of the outputs generated by forensic laboratories through which task oriented imperatives are performed and achieved.
The case files themselves are a somewhat “purified” version of the process of criminal investigation, insofar as the full details and order of events are not always comprehensible.
These are also inscribed with forensic reports provided to the criminal investigation police and to the cases’ prosecutors and investigating judges. Every trace, crime scene stain, suspect sample, or object that is received by the laboratory is subjected to a process of description, categorization, and translation, in order to isolate the materials from all kinds of contaminants, both physical and cognitive. This processhas been aptly described in Susana Costa’s ethnographic work in a Portuguese forensic laboratory (Costa 2003).This cognitive-instrumental membrane that separates the laboratoryfrom the outside world is important in a socio-legal context where the investigating police, the courts, and the official forensic laboratories are branches of the criminal justice system under the Ministry of Justice. Hence, what I have called the “epistemic distancing” of the forensic laboratories configures a professional ethos marked by distinctions and differentiations from the language, practices, classifications, hypothesis and opinions of the police.
Through purification, classification, and interpretative limitation, impure traces, stains and objects collected at crime scenes are scientifically translated in order to deliver “black boxed” results which conform to the organizational needs of the police and the criminal justice system.While the Portuguese criminal justice system could be characterized by a symbolic submission of law to science(Santos 2000), since expert evidence is not a matter to be freely assessedby the judge, during an investigation that submission is not absolute. Namely,becauseit is not the trial judge or jury who is to interpret the expert evidence, but the police investigators, prosecutors and investigating judges who will make sense of the laboratory results and inscribe them on the ongoing criminal narrative.Therefore, the process of investigating a crime allows interpretative flexibility along a forensic evidentiary chain until a case reaches trial. At this point, as Helena Machado argues, DNA technologies are perceived as transcendent of the contingencies of human action, and as a symbol of neutrality and truth (Machado 2012,280). Thus, the authoritative status of DNA technologies is seldom successfully challenged in court, as the complexities and uncertainties surrounding DNA evidence appear “black-boxed” and significantly framed in a criminal narrative that a defense lawyer is rarely prepared to successfully open (Dahl 2007,234).