RESUMO
Ensuring specimen validity is an essential aspect of toxicological laboratories. In recent years, substituting authentic urine specimens for synthetic urine (SU) has become increasingly popular. Such SU products consist of components expected in normal urine and show physiological values for specific gravity and pH. Thus, standard specimen validity testing may fail in revealing adulteration by SU. The present study investigated three methods to distinguish authentic and SU specimens: enzymatic detection of uric acid, the commercially available Axiom Test True SU and liquid chromatography coupled with (tandem) mass spectrometry (LC-MS-MS) analysis of 10 endogenous biomolecules. Additionally, novel direct markers of SU were investigated. Two specimen sets were analyzed by each method. Specimen set A consisted of eight SU products purchased from the Austrian/German market and 43 urine specimens from volunteers of known authenticity, which underwent double-blind analysis. Specimen set B consisted of 137 real urine specimens submitted for drug testing, which were selected due to initial suspicious test results in adulteration testing and reanalyzed by all three methods. Uric acid and LC-MS-MS-based endogenous biomolecule testing showed 100% sensitivity and specificity for set A. The commercial test had 87.5% sensitivity and 97.7% specificity for set A. For set B, uric acid and LC-MS-MS analysis showed almost similar results, even if uric acid was missing one presumptive authentic urine specimen according to LC-MS-MS findings. Nearly half of the SU assignments for the commercial test were presumptive false positives. New SU markers were observed for SU products from the Austrian/German market. One specimen in set B had both an endogenous biomolecule pattern and SU markers suggesting urine dilution with SU. In conclusion, several analytes or methods should be used rather than one, and the most reliable results are achieved if both indirect and direct markers of urine substitution are analyzed.
Assuntos
Espectrometria de Massa com Cromatografia Líquida , Espectrometria de Massas em Tandem , Humanos , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Ácido Úrico , Detecção do Abuso de Substâncias/métodosRESUMO
Temperature-based time of death estimation using simulation methods such as the finite element method promise higher accuracy and broader applicability in nonstandard cooling scenarios than established phenomenological methods. Their accuracy depends crucially on the simulation model to capture the actual situation, which in turn hinges on the representation of the corpse's anatomy in form of computational meshes as well as on the thermodynamic parameters. While inaccuracies in anatomy representation due to coarse mesh resolution are known to have a minor impact on the estimated time of death, the sensitivity with respect to larger differences in the anatomy has so far not been studied. We assess this sensitivity by comparing four independently generated and vastly different anatomical models in terms of the estimated time of death in an identical cooling scenario. In order to isolate the impact of shape variation, the models are scaled to a reference size, and the possible impact of measurement location variation is excluded explicitly by finding measurement locations leading to minimum deviations. The thus obtained lower bound on the impact of anatomy on the estimated time of death shows, that anatomy variations lead to deviations of at least 5-10%.
Assuntos
Temperatura Baixa , Humanos , Temperatura , Análise de Elementos Finitos , Simulação por ComputadorRESUMO
The reconstruction of traffic accidents involving powered two-wheelers (PTWs) frequently proves to be a challenging task. A case in which a fatal head-on crash of a PTW with a small truck where only minor vehicles damage was observed but resulted in isolated fatal chest trauma is discussed here. External examination of the corpse revealed two lacerations on the back, at the first glance implying sharp trauma. Based on the accident traces, the technical expert assumed an emergency break of the PTW rider resulting in a rotation of the PTW in terms of a wheelie on the front wheel. The first contact between the PTW rider and the tail end of the small truck probably occurred with the upper side of the helmet, and then, the back handle of the PTW caused the stab-like injuries followed by compression of the rider between the small truck or asphalt and the PTW. Based on the few accident traces available, neither a reconstruction of the pre-impact velocity nor a detailed reconstruction of the PTW rider kinematics was possible. However, using an interdisciplinary approach, the principal collision position as well as the injury mechanisms could be reconstructed.
Assuntos
Lacerações , Traumatismos Torácicos , Humanos , Acidentes de Trânsito , Motocicletas , Veículos AutomotoresRESUMO
In a previous article a new algorithm for fully automatic 'CT histogram based Fat Estimation and quasi-Segmentation' (CFES) was validated on synthetic data, on a special CT phantom, and tested on one corpse. Usage of said data in FE-modelling for temperature-based death time estimation is the investigation's number one long-term goal. The article presents CFES's results on a human corpse sample of size R = 32, evaluating three different performance measures: the τ-value, measuring the ability to differentiate fat from muscle, the anatomical fat-muscle misclassification rate D, and the weighted distance S between the empirical and the theoretical grey-scale value histogram. CFES-performance on the sample was: D = 3.6% for weight exponent α = 1, slightly higher for α ≥ 2 and much higher for α ≤ 0. Investigating τ, S and D on the sample revealed some unexpected results: While large values of τ imply small D-values, rising S implies falling D and there is a positive linear relationship between τ and S. The latter two findings seem to be counter-intuitive. Our Monte Carlo analysis detected a general umbrella type relation between τ and S, which seems to stem from a pivotal problem in fitting Normal mixture distributions.
Assuntos
Adiposidade , Humanos , Algoritmos , Cadáver , Tomografia Computadorizada por Raios XRESUMO
AIMS: Haemophagocytosis in the bone marrow of patients who have succumbed to coronavirus disease 19 (COVID-19) has not been widely studied. The aims of the present study were to perform morphological analyses and morphometry of haemophagocytosis in the bone marrow of patients with severe COVID-19, and to correlate the findings with the clinical course of the disease. METHODS AND RESULTS: In this single-centre study performed at the University Hospital Jena, bone marrow specimens of 15 deceased patients who had experienced a severe course of COVID-19 were sampled from the vertebral column during autopsy. Slides of the bone marrow were stained with routine stains or immunohistochemically, and further examined for haemophagocytosis by the use of light microscopy. To substantiate the morphological findings, additional slides were stained for CD163 and morphometry was performed. In all bone marrow samples, an increase in cellularity was found. Haemophagocytes with erythrophagocytosis were detected in 67% of the deceased patients. In tissues with low numbers of haemophagocytes or ill-defined haemophagocytes, an increase in iron deposits was frequently seen. Morphological findings were then correlated with several important clinical data, and the HScore (probability of having a reactive hemophagocytic syndrome) was calculated to posthumously confirm the diagnosis of secondary haemophagocytic lymphohistiocytosis. The median duration of disease and the hospitalisation time were lower in patients with haemophagocytosis (n = 10) than in patients without haemophagocytosis (n = 5). In addition, patients with haemophagocytes showed increased inflammatory parameters 2-5 days prior to death, in contrast to patients without haemophagocytes. CONCLUSIONS: Haemophagocytosis is a common finding in the bone marrow of deceased individuals with severe COVID-19, and may indicate fatal severe acute respiratory syndrome coronavirus 2 infections.
Assuntos
COVID-19/virologia , Linfo-Histiocitose Hemofagocítica/virologia , SARS-CoV-2/fisiologia , Idoso , Idoso de 80 Anos ou mais , Autopsia , Medula Óssea/patologia , Medula Óssea/virologia , COVID-19/complicações , COVID-19/patologia , Feminino , Hospitalização , Humanos , Imuno-Histoquímica , Linfo-Histiocitose Hemofagocítica/complicações , Linfo-Histiocitose Hemofagocítica/patologia , Masculino , Pessoa de Meia-IdadeRESUMO
Temperature based death time estimation (TDE) is severely limited in situations where body core temperature has almost decreased to ambient temperature. The TDE method of Marshall/Hoare and Henßge (MHH) defines a lower bound TK for body core temperature below which the time p.m. should be stated to be >10h only. A recent study (Potente et al., 2017 [10]) established a new method, called variance-bias-tradeoff (VBT) complementing MHH in constructing a right-side-half-infinite 97.5%-confidence interval for such 'near equilibrium'-situations. It seemingly proved the validity for all body core temperatures TAssuntos
Intervalos de Confiança
, Modelos Estatísticos
, Mudanças Depois da Morte
, Temperatura Corporal
, Medicina Legal/métodos
, Humanos
, Temperatura
RESUMO
PURPOSE: In forensic odontology the comparison between antemortem and postmortem panoramic radiographs (PRs) is a reliable method for person identification. The purpose of this study was to improve and automate identification of unknown people by comparison between antemortem and postmortem PR using computer vision. MATERIALS AND METHODS: The study includes 43â467 PRs from 24â545 patients (46â% females/54â% males). All PRs were filtered and evaluated with Matlab R2014b including the toolboxes image processing and computer vision system. The matching process used the SURF feature to find the corresponding points between two PRs (unknown person and database entry) out of the whole database. RESULTS: From 40 randomly selected persons, 34 persons (85â%) could be reliably identified by corresponding PR matching points between an already existing scan in the database and the most recent PR. The systematic matching yielded a maximum of 259 points for a successful identification between two different PRs of the same person and a maximum of 12 corresponding matching points for other non-identical persons in the database. Hence 12 matching points are the threshold for reliable assignment. CONCLUSION: Operating with an automatic PR system and computer vision could be a successful and reliable tool for identification purposes. The applied method distinguishes itself by virtue of its fast and reliable identification of persons by PR. This Identification method is suitable even if dental characteristics were removed or added in the past. The system seems to be robust for large amounts of data. KEY POINTS: · Computer vision allows an automated antemortem and postmortem comparison of panoramic radiographs (PRs) for person identification.. · The present method is able to find identical matching partners among huge datasets (big data) in a short computing time.. · The identification method is suitable even if dental characteristics were removed or added.. CITATION FORMAT: · Heinrich A, Güttler F, Wendt S etâal. Forensic Odontology: Automatic Identification of Persons Comparing Antemortem and Postmortem Panoramic Radiographs Using Computer Vision. Fortschr Röntgenstr 2018; 190: 1152â-â1158.
Assuntos
Inteligência Artificial , Odontologia Legal/métodos , Processamento de Imagem Assistida por Computador/métodos , Radiografia Panorâmica/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Criança , Conjuntos de Dados como Assunto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Post-mortem body cooling is the foundation of temperature-based death time estimations (TDE) in homicide cases. Forensic science generally provides two types of p.m. body cooling models, the phenomenological and the physical models. Since both of them have to implement important individual parameters like the quantity of abdominal fat explicitly or implicitly, a more exact quantification and localization of abdominal fat is a desideratum in TDE. Particularly for the physical models, a better knowledge of the abdominal fat distribution could lead to relevant improvements in TDEs. Modern imaging methods in medicine like computed tomography (CT) are opening up the possibility to register the quantity and spatial distribution of body fat in individual cases with unprecedented precision. Since a CT-scan of an individual's abdominal region can comprise 1000 slices as an order of magnitude, it is evident that their evaluation for body fat quantification and localization needs fully automated algorithms. The paper at hand describes the development and validation of such an algorithm called "CT-histogram-based fat estimation and quasi-segmentation" (CFES). The approach can be characterized as a weighted least squares method dealing with the gray value histogram of single CT-slices only. It does not require any anatomical a priori information nor does it perform time-consuming feature detection on the CT-images. The processing result consists in numbers quantifying the amount of abdominal body fat and of muscle-, organ-, and connective tissue. As a by-product, CFES generates a quasi-segmentation of the slices processed differentiating fat from muscle-, organ-, and connective tissue. The tool is validated on synthetic data and on CT-data of a special phantom. It was also applied on a CT-scan of a dead body, where it produced anatomically plausible results.
Assuntos
Gordura Abdominal/diagnóstico por imagem , Algoritmos , Imagens de Fantasmas , Tomografia Computadorizada por Raios X , Adulto , Temperatura Corporal , Patologia Legal , Humanos , Análise dos Mínimos Quadrados , Masculino , Mudanças Depois da MorteRESUMO
Fatal bicycle-pedestrian collisions do not occur frequently and thus are rarely reported in literature. Pedestrians in bicycle-pedestrian accidents often sustain severe craniocerebral injuries caused by a collision induced fall with head impact on the road surface. We describe a case where a pedestrian crossing a road was hit by a bicycle. Hematomas of the left lower leg and of the left flank/abdomen were found to be caused by the primary impact. However, the fatal injuries were found to be contralateral with a rupture of the right renal pedicle, a rupture of the right lobe of the liver and a tear of the vena cava. Neither the bicycle impact nor a fall onto the road surface could cause these injuries. Multibody simulation (PC Crash 9.2) revealed entanglement between the bicyclist and the pedestrian followed by a contact interaction between the pedestrian laying on the road surface and the falling bicyclist. In forensic case work post-crash contact interactions between the bicyclist and the pedestrian should be considered as a potential source of severe injuries.
Assuntos
Ciclismo , Simulação por Computador , Pedestres , Fenômenos Biomecânicos , Exsanguinação/etiologia , Evolução Fatal , Feminino , Medicina Legal/métodos , Hematoma/patologia , Humanos , Rim/lesões , Rim/patologia , Fígado/lesões , Fígado/patologia , Pessoa de Meia-Idade , Ruptura , Software , Veias Cavas/lesões , Veias Cavas/patologiaRESUMO
Temperature-based death time estimation is based either on simple phenomenological models of corpse cooling or on detailed physical heat transfer models. The latter are much more complex but allow a higher accuracy of death time estimation, as in principle, all relevant cooling mechanisms can be taken into account.Here, a complete workflow for finite element-based cooling simulation is presented. The following steps are demonstrated on a CT phantom: Computer tomography (CT) scan Segmentation of the CT images for thermodynamically relevant features of individual geometries and compilation in a geometric computer-aided design (CAD) model Conversion of the segmentation result into a finite element (FE) simulation model Computation of the model cooling curve (MOD) Calculation of the cooling time (CTE) For the first time in FE-based cooling time estimation, the steps from the CT image over segmentation to FE model generation are performed semi-automatically. The cooling time calculation results are compared to cooling measurements performed on the phantoms under controlled conditions. In this context, the method is validated using a CT phantom. Some of the phantoms' thermodynamic material parameters had to be determined via independent experiments.Moreover, the impact of geometry and material parameter uncertainties on the estimated cooling time is investigated by a sensitivity analysis.
Assuntos
Simulação por Computador , Análise de Elementos Finitos , Mudanças Depois da Morte , Desenho Assistido por Computador , Estudos de Viabilidade , Humanos , Modelos Biológicos , Tomografia Computadorizada Multidetectores , Imagens de FantasmasRESUMO
Forensic case work as well as literature shows that severe head injuries, e.g., with basilar fractures and cerebral hemorrhages due to stomps can be seen; however, there is no data basis concerning contact forces and potential influencing factors. The objective of this work was to generate a data basis of contact forces in stomping by performing experimental measurements and subsequent statistical analyses. Fifty-five volunteers participated in the present study. Each participant performed several stomps onto force plates with sturdy/soft footwear as well as with/without an elastic layer imitating the scalp. Ground reaction forces induced by jumps were also measured for sturdy and soft footwear. The results show statistically significant dependencies between maximum ground reaction forces and body weight and body height. A statistically significant influence of footwear on stomping force could only be found in tests with an elastic layer and in the jumping setup. Mean maximum stomping forces for the female volunteers were between 4694 and 5970 N; male volunteers were able to produce mean peak stomping forces between 8494 and 9016 N. Jumping forces were approximately twice the stomping forces for both male and female test persons. Regardless of footwear and gender, it can be claimed that a forceful stomp or jump to someone's head supported on the ground can cause facial and skull fractures. Thus, forceful stomps or jumps to someone's head can cause potential fatal injuries independent of footwear, gender, or fitness level.
Assuntos
Fenômenos Biomecânicos/fisiologia , Traumatismos Cranianos Fechados/fisiopatologia , Adulto , Estatura/fisiologia , Peso Corporal/fisiologia , Feminino , Ciências Forenses , Humanos , Masculino , Pessoa de Meia-Idade , Sapatos , Adulto JovemRESUMO
Marshall and Hoare's double exponential model with Henßge's parameters is a well known method for temperature based death time estimation. The authors give 95%-confidence intervals for their method. Since body cooling is a complex thermodynamical process, one has to take into account a potential bias of the estimator. This quantity measures the systematic error of the estimators underlying model. For confidence interval radius calculation a bias of 0 is presupposed, therefore the actual probability of the true death time value to lie in the 95%-confidence interval can be much lower than 95% in case of nonvanishing bias. As in case of nonstandard conditions the confidence intervals have a probability of containing the true death time value which even in case of small corrective factor errors of Δ = ± 0.1 can be substantially smaller than the 95% claimed, the paper presents a formula for confidence intervals which keep a 95% probability in case of error Δc ⩽ ± 0.1.
Assuntos
Temperatura Corporal , Intervalos de Confiança , Morte , Medicina Legal , Humanos , Mudanças Depois da Morte , Fatores de TempoRESUMO
Bayesian estimation applied to temperature based death time estimation was recently introduced as conditional probability distribution or CPD-method by Biermann and Potente. The CPD-method is useful, if there is external information that sets the boundaries of the true death time interval (victim last seen alive and found dead). CPD allows computation of probabilities for small time intervals of interest (e.g. no-alibi intervals of suspects) within the large true death time interval. In the light of the importance of the CPD for conviction or acquittal of suspects the present study identifies a potential error source. Deviations in death time estimates will cause errors in the CPD-computed probabilities. We derive formulae to quantify the CPD error as a function of input error. Moreover we observed the paradox, that in cases, in which the small no-alibi time interval is located at the boundary of the true death time interval, adjacent to the erroneous death time estimate, CPD-computed probabilities for that small no-alibi interval will increase with increasing input deviation, else the CPD-computed probabilities will decrease. We therefore advise not to use CPD if there is an indication of an error or a contra-empirical deviation in the death time estimates, that is especially, if the death time estimates fall out of the true death time interval, even if the 95%-confidence intervals of the estimate still overlap the true death time interval.
Assuntos
Temperatura Corporal , Mudanças Depois da Morte , Probabilidade , Medicina Legal , Humanos , Funções VerossimilhançaRESUMO
In the case presented, conflicting witness accounts and the subject's injuries were highly suspicious of an assault that might have caused the balcony fall. For the reconstruction, a simulation software, originally designed for motor vehicle accident reconstruction, was used. Three scenarios were simulated using the PC-Crash multibody pedestrian model: (S1) Subject was pushed against and fell over balcony rail, (S2) subject fell off from a seated position, (S3) subject fell off from a prone position on the rail. (S1) could be ruled out due to inconsistent results in terms of landing area and minimum velocity. Realistic results were obtained for (S3) with a fall off from a prone position on the rail. After a few months, the comatose subject awoke and gave an account of what had happened being consistent with the simulation results. This case demonstrates the feasibility of multibody simulations also in cases of nontraffic incidents.
Assuntos
Acidentes por Quedas , Simulação por Computador , Homicídio , Modelos Biológicos , Software , Fenômenos Biomecânicos , Estudos de Viabilidade , Ciências Forenses/métodos , Fraturas Ósseas/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Traumatismo Múltiplo/etiologiaRESUMO
For an expert opinion, the course of events in a conflict resulting in a 3 cm deep and 1.8 cm wide stab wound on the neck of a woman was to be reconstructed. Based on the statements of witnesses, there were three possible scenarios: 1. The knife was thrown from a distance of about one meter. 2. The knife had accidentally slipped from the hand. 3. The knife was deliberately used for a stab to the neck of the victim. The experimental setup comprised the knife presumably causing the injury and four comparable knives. The victim was represented by a pig carcass. The results of the test throws are presented and the sequence of movements is assessed as to the most probable course of events. Four male and three female subjects performed test throws which were documented by video recordings and measurements of the penetration depth. Six of the seven subjects were able to generate stab wounds by throwing the knives, whereas a knife accidentally slipping from the hand never caused a stab wound in the tests.
Assuntos
Prova Pericial/legislação & jurisprudência , Lesões do Pescoço/patologia , Maus-Tratos Conjugais/legislação & jurisprudência , Armas/legislação & jurisprudência , Ferimentos Perfurantes/patologia , Acidentes/legislação & jurisprudência , Fenômenos Biomecânicos , Diagnóstico Diferencial , Feminino , HumanosRESUMO
Kinship relation and, in particular, paternity probability estimation using a Bayesian approach require the input of a priori probabilities of different hypotheses. In practical case work, a priori probabilities or priors, for short, must often be estimated using only common sense and symmetry arguments because in most cases, there is no evidence-based information on which the priors may be determined. In contrast to the accuracy of the likelihood probabilities or the likelihood ratios, the precision of the priors is usually very poor. Thus, a quantitative estimation of the priors' influence on the paternity probability is desirable. This article presents exact formulae to define sharp minimum and maximum boundaries of posterior probabilities as a function of prior boundaries which may be applied in kinship cases with varying numbers of hypotheses and also presents two case examples.
Assuntos
Teorema de Bayes , Família , Funções Verossimilhança , Paternidade , Teoria da Probabilidade , Algoritmos , Genética Forense , Marcadores Genéticos/genética , GenótipoRESUMO
The most common method used in determining the estimated time since death in the early post-mortem phase is back-calculation based on rectal temperature decrease. Cooling experiments are essential for model generation and validation. Post-mortem temperature models are necessary to perform back-calculations. Thus far, cooling experiments have not been performed under controlled environmental conditions. The present study provides data on 84 post-mortem cooling experiments under strictly controlled environmental conditions. For a period of 5 years, starting in 2003, deceased persons with a known time of death and known environmental conditions at the death scene were transferred to a climatic chamber for the process of body cooling. The environmental temperature was programmed to the death scene temperature and kept constant throughout the process of body cooling. Rectal and ambient temperatures were measured every minute. Relevant case-specific information was summarized in a FileMaker database. The database serves as a reference tool for the comparison of real cases in forensic routine and to check the plausibility of model-derived estimates.
Assuntos
Temperatura Corporal , Medicina Legal , Mudanças Depois da Morte , Reto , Adulto , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de TempoRESUMO
Model-based methods play an important role in temperature-based death time determination. The most prominent method uses Marshall and Hoare's double exponential model with Henssge's parameter determination. The formulae contain body mass as the only non-temperature parameter. Henssge's method is well established since it can be adapted to non-standard cooling situations varying the parameter body mass by multiplying it with the corrective factor. The present study investigates the influence of measurement errors of body mass m as well as of variations of the corrective factor c on the error of the Marshall and Hoare-Henssge death time estimator t (D). A formula for the relative error of t (D) as a function of the relative error of m is derived. Simple approximations of order 1 and 0 nevertheless yield acceptable results validated by Monte Carlo simulations. They also provide the rule of thumb according to which the quotient of the standard deviations D(t (D)) of the estimated death time and D(m) of the body mass is equal to the quotient of the estimated death time t (D) and the body mass m (D(t (D))/D(m) ≈ t (D)/m). Additionally, formulae and their approximations are derived to quantify the influence of Henssge's body mass corrective factor c on death time estimation. In a range of body masses between 50 and 150 kg, the relative variation of the body mass corrective factor is approximately equal to the relative variation of the death time (Δt (D) = (t (D)/c)Δc). This formula is applied and compared to computations and to experimental cooling data with good results.
Assuntos
Índice de Massa Corporal , Temperatura Corporal , Mudanças Depois da Morte , Morte , Medicina Legal , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de TempoRESUMO
Temperature-based methods represent essential tools in forensic death time determination. Empirical double exponential models have gained wide acceptance because they are highly flexible and simple to handle. The most established model commonly used in forensic practice was developed by Henssge. It contains three independent variables: the body mass, the environmental temperature, and the initial body core temperature. The present study investigates the influence of variations in the input data (environmental temperature, initial body core temperature, core temperature, time) on the standard deviation of the model-based estimates of the time since death. Two different approaches were used for calculating the standard deviation: the law of error propagation and the Monte Carlo method. Errors in environmental temperature measurements as well as deviations of the initial rectal temperature were identified as major sources of inaccuracies in model based death time estimation.
Assuntos
Autopsia/métodos , Temperatura Corporal , Medicina Legal/métodos , Mudanças Depois da Morte , Temperatura , Algoritmos , Humanos , Método de Monte Carlo , Valor Preditivo dos Testes , Processos Estocásticos , Fatores de TempoRESUMO
The temperature-oriented death time determination is based on mathematical model curves of postmortem rectal cooling. All mathematical models require knowledge of the environmental conditions. In medico-legal practice homicide is sometimes not immediately suspected at the death scene but afterwards during external examination of the body. The environmental temperature at the death scene remains unknown or can only be roughly reconstructed. In such cases the question arises whether it is possible to estimate the time since death from rectal temperature data alone recorded over a longer time span. The present study theoretically deduces formulae which are independent of the initial and environmental temperatures and thus proves that the information needed for death time estimation is contained in the rectal temperature data. Since the environmental temperature at the death scene may differ from that during the temperature recording, an additional factor has to be used. This is that the body core is thermally well isolated from the environment and that the rectal temperature decrease after a sudden change of environmental temperature will continue for some time at a rate similar to that before the sudden change. The present study further provides a curve-fitting procedure for such scenarios. The procedure was tested in rectal cooling data of from 35 corpses using the most commonly applied model of Henssge. In all cases the time of death was exactly known. After admission to the medico-legal institute the bodies were kept at a constant environmental temperature for 12-36 h and the rectal temperatures were recorded continuously. The curve-fitting procedure led to valid estimates of the time since death in all experiments despite the unknown environmental conditions before admission to the institute. The estimation bias was investigated statistically. The 95% confidence intervals amounted to +/-4 h, which seems reasonable compared to the 95% confidence intervals of the Henssge model with known environmental temperature. The presented method may be of use for determining the time since death even in cases in which the environmental temperature and rectal temperature at the death scene have unintentionally not been recorded.