Preserved brains from the Spanish Civil War mass grave (1936) at La Pedraja1, Burgos, Spain
Introduction
The Spanish Civil War began on the 18th July 1936 with a military coup lead by General Franco against the elected, leftist government of the Second Spanish Republic. From July to December of 1936, several towns and villages in the South of Spain were violently occupied by the fascist regime, while in the North they took many towns without much resistance [1], [2], [3]. During those months, there was no battlefront and most deaths were the result of executions by the fascist rebel army, police and its civil supporters (falangistas), but also to some extent by the Republican forces. It has been estimated that 130.000 people were killed in this way by the rebel army with the goal of terrorising the population. In the territories occupied by the fascists, political representatives, who had been democratically elected, were arrested and killed. In the northern province of Burgos, for instance, 1000 people, 400 of them from the city of Burgos alone, were executed and buried in clandestine mass graves similar to that at La Pedraja. The Spanish Civil War was the final result of the failure of the military coup and ended on the 1st April 1939 with the victory of the rebel army, with more than 500.000 people dead and about 450.000 in exile. Franco was the head of the Spanish state from 1939 to his death in 1975. Although Franco recovered, identified and returned the remains of fascist who had been killed to their families, most of the republican victims are still missing and buried in clandestine mass graves such as La Pedraja. [1], [2], [3].
At the end of the 1990s, a social movement called ‘Historical Memory’ (Memoria Histórica) was set up, with the aim of recovering and identifying the missing people from the Spanish Civil War. In the year 2000, the Asociación para la Recuperación de la Memoria Histórica de Ponferrada (The Ponferrada Association for the Recovery of Historical Memory) at the request of the families of the missing, began the first scientific coordinated search to locate and excavate human remains from a mass grave in Priaranza del Bierzo (León), using archaeological techniques and following forensic protocols [4], [5]. The case of Priaranza del Bierzo became a prime example and other teams in Spain began to locate and excavate human remains buried in mass graves. From 2000 to 2008, the Government did not support the families of the victims in their search for their relatives. However, in 2008, the excavation of most mass graves started to have the support of the Ministry of the Presidency of the Spanish Government and several Regional Governments. Also in 2008, a National Penal Court (Sala de Lo Penal de la Audiencia Nacional) decided that Spanish Civil War mass graves could be opened by the Local Courts (Juzgados de Instrucción), but only a few judges opened a judicial process to search, locate, study and identify individuals found in mass graves. The Spanish Government, however, only arranged funds to recover theses victims between 2008 and 2011. In 2014, the special advisor of the United Nations visited Spain, and stated that the Spanish state must take responsibility for the victims, and must give support to families with regard to the search and identification of their missing relatives. Despite international pressure, however, financial support for these works has decreased since 2011 [7]. At present (2016), the families of the missing are searching, locating and identifying their loved ones with the help of volunteers and with very limited budgets. Although there is no official register, it is estimated that from the over 2200 mass graves identified in Spain, about 7,000 people have been recovered from just over 300 mass grave excavations (Spanish Government, 2016) [6]. One of the largest mass graves to have been excavated was that of La Pedraja 1 in the Province of Burgos, excavated in 2010 and revealing a total number of 104 individuals (Fig. 1).
After locating the site in 2010, the excavation of the mass grave of La Pedraja 1 was undertaken by the Aranzadi Society of Sciences (ASS, Sociedad de Ciencias Aranzadi), an independent and non-governmental organization. This organization aims to search, recover and identify the missing people, in particular from the Spanish Civil Wars by employing scientific methods and following international forensic protocols such as the United Nations Manual on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions and Recommendation no. R (99) 3 of the Committee of Ministers to member states of the European Union on theharmonisation of medico-legal autopsy rules. In 2000, the ASS created a Historical, Archaeological and Anthropological Team of volunteers to participate in the investigation of crimes against humanity. Thus, the mass grave of La Pedraja 1 was considered a crime scene and was excavated following forensic archaeological methods, principles and theory.
Nevertheless and much to the surprise of the excavation team at La Pedraja 1, 45 (43.2%) of the exhumed individuals had what appeared to be brain matter surviving within their skulls. Thus, a multidisciplinary team was created to study these remains within a forensic perspective. The aim of the research was to confirm that the material was indeed human brain tissue, investigate how and why this tissue had been preserved for approximately 80 years; and finally to establish if this material, alongside information derived from the forensic anthropology examination of the skeletal remains, could provide information regarding the identity of the deceased and the cause and manner of death.
The importance of La Pedraja 1 in advancing the understanding of this phenomenon is that, unlike other archaeological examples, the recent date of this mass grave means that there is a range of documentary and anecdotal historical evidence to complement and supplement the archaeological data. From these historical sources, a more detailed picture of the life and death of the individuals can be drawn, which may assist in the interpretation of the factors influencing the taphonomic processed which have led to the survival of the brain tissue. Understanding these interrelated factors more fully may have significant repercussions for both archaeological and forensic studies, if brain survival in otherwise skeletonised remains reveals circumstances surrounding the death of an individual that cannot be determined in any other way.
Section snippets
The excavation of mass graves at La Pedraja 1
La Pedraja is a mountain pass located at Villafranca de Montes de Oca, rising to 1155 m above sea level, some 30 km east of Burgos and close to the road connecting the cities of Burgos and Logroño (Fig. 1).
It had been known since the Civil War that this pass had been the site of mass executions, but the exact location of the graves was only confirmed by geophysical survey in 2010. Two mass graves were discovered at approximately 1100 m above sea level and designated La Pedraja 1 (42° 22′ 24. 64″ N
Taphonomic study of the brains
After recording every brain, three brains were selected for detailed taphonomic analysis. These were chosen based on their level of preservation and because they retained both cerebral hemispheres. In addition, soil samples obtained from the mass grave were taken for physical, chemical and geo-chemical analyses. The study was designed to address several questions: the nature of the burial environment, how and why preservation of the brains had occurred, to what extent brain histology was still
Crime scene analysis
Historical data indicated that most of the deceased came from regions near to where they were buried and had been illegally detained by supporters of the rebel army at different places and times. They remained kidnapped for a few hours or days and later executed, mostly by handguns. The historical data also indicated that the identities of the dead were not certain, although we know that the majority of the missing were young adult men. It is not surprising to see this at La Pedraja, since this
Conclusions
To conclude, this study has demonstrated that the scientific knowledge of taphonomic processes is difficult although interesting, as it could contribute to the administration of Justice in a forensic anthropology context. The following points are highlighted:
The hypothesis that these brains have been preserved by a humid mechanism linked to the process of saponification through adipocere formation, is maintained. The chemical study confirms that the brains possess a chemical profile of
Conflict of interest
The authors declare that they have no conflict of interest.
Acknowledgments
To Sonia O’Connor who helped with the English and organisation of the text. The authors thank Professor Ana Maria Bravo del Moral for her critical review and technical comments of the manuscript. To the team at the Service of Radiology, Hospital de Verin, especially Cruz Galindo, Jose Manuel Coello and Jorge Basteiro, for the MRI and CT studies. Our thanks also go to Gemma Prats-Munoz, Glen Doran, Sergio Cardoso, Marian Martinez de Pancorbo, Juan Ramon Vidal Romani and the Aranzadi Science
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