J Forensic Sci, Sept. 2004, Vol. 49, No. 5 Paper ID JFS2003337 Available online at: www.astm.org TECHNICAL NOTE Jos´ e L. Prieto, 1 M.D., D.D.S; Concepci ´ on Maga˜ na, 1 B.B; and Douglas H.Ubelaker, 2 Ph.D. Interpretation of Postmortem Change in Cadavers in Spain ABSTRACT: Estimating time since death is especially difficult in the examination of poorly preserved cadavers and depends on the experience of the examiner and comparison with previously documented cases showing similar characteristics. The present study reports on information obtained over the past ten years through the work of the Laboratorio de Antropolog´ ıa y Odontolog´ ıa Forense (LAF) of the Instituto Anat ´ omico Forense de Madrid, Spain, in particular evaluating how the type of fracture influences postmortem change. From the original 225 forensic cases examined between 1992 and 2002 in the LAF, a sample of 29 cases were selected from various regions of the Spanish mainland. A data collection protocol was established to reflect factors which the existing specialized literature, documenting the relation existing in the sample analyzed between time since death and the extent of postmortem change, which in the environments examined are distributed into the following phases: Phase 1 (putrefaction): one week to one month on the surface and two months in water. Phase 2 (initial skeletonization): two months on the surface and five to six months in water. Phase 3 (advanced skeltonization): six months to 1.5 years on the surface and 2.5 years buried. Phase 4 (complete skeletonization): about one year on the surface and three years buried. This paper also provide useful information on the impact of carrion insect activity, location, climate, seasonality, and predator. KEYWORDS: forensic science, forensic anthropology, postmortem interval (PMI), human taphonomy, Spain Estimating time since death is one of the largest and most com- mon problems facing forensic medical specialists, and is essential to establish the final activities of the victim and the possible identity of suspects. Unfortunately, it is also one of the most difficult issues to resolve. The uncertainty regarding calculation of postmortem interval (PMI) increases considerably with the advance of the destructive processes. In cases of partial decomposition or total skeletonization the difficulties of assessment can be quite profound. Numerous factors have been identified as being responsible for the postmortem change in the cadaver (9). These factors, which are intimately related, can be classified into two groups: (1) those which are dependent on the cadaver or intrinsic factors, and (2) those dependent on the postmortem environment of the cadaver or extrinsic factors (temperature, humidity, insect activity, foraging animals). Several studies have attempted to produce objective methodology to estimate time since death in human remains. Examples include evaluation of biomarkers like lipids, nitrogen, amino acid content, neurotransmitters, and decompositional by-products (1,8,23,24), persistence of blood remnants in bone tissue (6), the extent of DNA deterioration (15), changes sustained by micro anatomical skeletal structure (25), and even C-14 (22). Although the studies provided useful information, no accepted practical method currently exists 1 Laboratorio de Antropolog´ ıa y Odontolog´ ıa Forense; Instituto Anat´ omico Forense, Madrid, 28040. 2 Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560. Received 1 Oct. 2003; and in revised form 3 April 2004; accepted 3 April 2004; published 4 Aug. 2004. enabling determination of time since death in such cases. Such de- terminations must be made on an individual and empirical basis, drawing from the personal experiences of the examiner and subjec- tive comparison of each case with others of similar characteristics. Other studies have attempted to analyze and calibrate postmortem change, and elucidate the influencing factors. These contributions have documented the general sequence of postmortem change stages present in the assessment of time since death in a particular case. Some of these studies evaluate experimental data (e.g., 19) while others retrospectively analyze existing documented cases, noting the sequence of change (e.g., 3,18). These studies seem to show the major role played by geographical location and environ- mental factors in the rate and nature of postmortem change. The aim of this contribution is to summarize our observations on postmortem change in the Spanish environment in which we work, in the Laboratorio de Antropolog´ ıa y Odontolog´ ıa Forense of the Instituto Anat´ omico Forense de Madrid (LAF). This analysis will allow us to understand the changes in evolution of the postmortem process in our environment and which factors must be contemplated to establish time since death in cases of advanced decomposition. Hopefully this study provides useful insights to colleagues working in other regions who face similar forensic problems. Materials and Methods Geographic Location The Spanish mainland territory forms part of the southern penin- sula in Europe (area: 492,991 km 2 ), located in the land mass sep- arating the Atlantic Ocean and the Mediterranean Sea. Spain is Copyright C  2004 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. 1