Death time estimation in case work. II. Integration of different methods

The mean value of the time of death is not reliable because of the great variability of the time-dependent criteria of dead bodies. However, it is possible to narrow down a reliable time period for a stated death by means of the lower and upper limits of error of different criteria. The external data of lividity, rigor, mechanical and electrical excitability of facial muscles and the chemical excitability of the iris have all been gathered from literature, chronologically arranged and clearly presented. After rectal temperature measurement and a corresponding nomogram reading, it is simple to choose other suitable criteria and to integrate them with the aid of a chart thus producing a rational and practical procedure for use at a scene of crime.     

Use of rectal temperature-time of death nomograms at the scene of death

The application of the rectal temperature time of death nomogram at the scene of death by 11 authors from 6 lego-medical institutes resulted in a standard deviation of the differences between nomographic and real death time of +/- 1.3 h in 46 cases (group I) with met requirements and clearly defined points of contact, nevertheless, including 9 cases with a more progressive cooling (0.5 greater than Q greater than or equal to 0.2). In cases with a real death time of more than 4h (N = 26) the standard deviation was +/- 1.0 hours corresponding to permissible variation of 95% of +/- 2.0 hours. Consequently, the permissible variation of 95% was much smaller than that suggested by the nomogram. The nomographic death time interval did not agree with the real one in 5 cases out of additional 30 cases with recognizably unsure points of contact (group II).     

Entomological and Cardiologic Evidence of Time Since Death in Short Postmortem Intervals

Estimating the time since death of the deceased is a main goal in forensic investigations, but this can be challenging due to contradictory results derived from different investigations at the scene of death. We present a case of a 78‐year‐old woman, found dead in a small forest with broad‐leaved trees, whose husband had a history of domestic violence. Routinely performed investigations, such as postmortem rectal temperature and lividity, yielded inconsistent time since death results between only a few and longer than 20 h. This difficulty was most likely caused by high ambient temperatures of up to 38.0°C, which negatively influenced the informative value of the applied nomogram method. Additionally, performed entomological investigation of fly maggots (Lucilia illustris) recovered from the corpse and the assessment of heart pacemaker data revealed consistent and incontrovertible results. The presented case highlights the benefits of information provided by entomological investigations and data evaluation of cardiac implantable electronic devices and the combined use of the two techniques.     

Time of death of victims found in cold water environment

Limited data is available on the application of post-mortem temperature methods to non-standard conditions, especially in problematic real life cases in which the body of the victim is found in cold water environment. Here we present our experience on two cases with known post-mortem times. A 14-year-old girl (rectal temperature 15.5 degrees C) was found assaulted and drowned after a rainy cold night (+5 degrees C) in wet clothing (four layers) at the bottom of a shallow ditch, lying in non-flowing water. The post-mortem time turned out to be 15-16 h. Four days later, at the same time in the morning, after a cold (+/- 0 degrees C) night, a young man (rectal temperature 10.8 degrees C) was found drowned in a shallow cold drain (+4 degrees C) wearing similar clothing (four layers) and being exposed to almost similar environmental and weather conditions, except of flow (7.7 l/s or 0.3 m/s) in the drain. The post-mortem time was deduced to be 10-12 h. We tested the applicability of five practical methods to estimate time of death. Henssge's temperature-time of death nomogram method with correction factors was the most versatile and gave also most accurate results, although there is limited data on choosing of correction factors. In the first case, the right correction factor was close to 1.0 (recommended 1.1-1.2), suggesting that wet clothing acted like dry clothing in slowing down body cooling. In the second case, the right correction factor was between 0.3 and 0.5, similar to the recommended 0.35 for naked bodies in flowing water.     

依据Marshall和Hoare的数学模型推断死亡时间的新方法

在对Marshall和Hoare的尸体直肠冷却数学模型做进一步研究的基础上,建立了一种适于在环境温度为3°～24℃时推定死亡时间的新方法。用本法检测34具机械性损伤尸体与国内的两种计算方法比较,效果较优,于死后15小时内进行168次计算,误差在±1小时内的为57.1％～77.7％,它能较好地反映个体差异,因而比Marshall等的原方法更能客观地反映直肠冷却规律。     

大鼠死后腓肠肌直接电兴奋性变化与早期死亡时间的关系

目的探讨大鼠死亡后不同时间腓肠肌电兴奋性的变化,为早期死亡时间的推断提供新的指标。方法建立大鼠机械性窒息模型,利用电生理检测仪检测死亡后不同时间大鼠腓肠肌对不同强度的电刺激的反应性,记录肌肉组织动作电位出现时间,统计学分析其差异并建立回归方程。结果大鼠机械性窒息死亡后一定时间内,其腓肠肌对电刺激的兴奋性与死亡时间呈明显线性关系。结论肌肉组织的电兴奋性可以作为早期死亡时间推断的有效指标。     

First practical applications of eye temperature measurements for estimation of the time of death in casework. Report of three cases

This paper presents first three successive cases of death where at scene measurements of the internal eyeball temperature soon after death allowed to precisely estimate the times of deaths based on this data (33.1°C, 32.2°C and 29.5°C, respectively), which were later confirmed during the police investigation. Simultaneously the rectal temperatures in all three cases were measured and appeared to be between 36.3 and 36.8°C-reflecting a living individual's body temperature. Thanks to a significantly faster postmortem decrease of the eye temperature and a residual or nonexistent plateau effect affecting the eye, using the formula developed in previous comprehensive studies in pigs, the time of death in real cases could be estimated with good precision: 1 h 33 min, 2 h 24 min and 3 h 17 min since death respectively. The actual TOD established during investigation appeared to be: between 1 h 30 min and 1 h 50 min in case 1; 1 h 55 min in case 2 and between 2 h 55 min and 3 h 05 min in case 3. Such precise estimation, mainly due to the plateau effect lasting up to a few hours, could not have been done based only on rectal temperature, commonly measured in forensic practice.     

Multiple-probe thermography for estimating the postmortem interval: II. Practical versions of the Triple-Exponential Formulae (TEF) for estimating the time of death in the field

A simple, reliable, and relatively accurate method for estimating the time since death is described. It is based on the Triple-Exponential Formulae (TEF), which are devised for the first time in this study. The postmortem cooling rate of the brain, liver, and rectum in 117 forensic cases were investigated (Part I). The method can be used in the field as a computer program, reference graph, or reference chart-ruler. The program is simple and can easily be run by any user. There are six reference graphs representing the average brain, liver, and rectal cooling curves for naked and covered body groups. The ruler is designed for the rectal cooling curves for covered and naked bodies. This method requires one temperature measurement of the chosen body site and the environment. The postmortem interval is estimated as a probable value +/- a possible range of time estimates with a built-in confidence limit.     

Influence of electricity on post-mortal body temperature

In a case of suicidal application of electricity differences between the rectal temperature of the body and the suspected time of death were observed. In order to answer the question whether an electric current from hand to hand over >30 min led to a rise in body temperature FEM-based computer simulations and animal experiments were carried out. Both resulted in a warming of the soft parts in the arm without warming the body core. Thus a temperature-based estimation of the time since death can also be used in cases with electricity as the cause of death. Besides, in the animal experiment we found a spontaneous rise in the body core temperature even without application of electricity which may be a reason for the typical temperature plateau after death.     

脑死亡若干法律问题研究

脑死亡是刑法学中与人的生命保护界限密切相关的问题。脑死亡的新观念虽然面临挑战 ,但其科学合理性毋庸置疑。脑死亡的时间应当以全脑机能不可逆性丧失时为准。脑死亡的概念与判定标准 ,有必要在器官移植法中予以规定。     

Thermometry of cadavers

The purpose of this study was to analyze the norm-setting documents on the order of thermometry, regulating the steps of physician during examination at the site where the cadaver was found and of medical expert during expert evaluations and to disclose the relationship between the depth to which the thermometer is inserted during measurements of rectal temperature and thermometry value. The following conclusions are made: 1) even at the same time of death, the data of rectal thermometry are in direct proportion to the depth to which the thermometer is inserted into the rectum; 2) some assumptions in the norm-setting documents regulating the order of cadaver thermometry are to be revised; and 3) thermometers and method of thermometry performed by medical specialists at the site of accident and by experts at thanatological departments of Bureaus of Forensic Medical Expert Evaluations are to be standardized.     

Influence of electricity on post-mortal body temperature

In a case of suicidal application of electricity differences between the rectal temperature of the body and the suspected time of death were observed.In order to answer the question whether an electric current from hand to hand over >30 min led to a rise in body temperature FEM-based computer simulations and animal experiments were carried out. Both resulted in a warming of the soft parts in the arm without warming the body core. Thus a temperature-based estimation of the time since death can also be used in cases with electricity as the cause of death. Besides, in the animal experiment we found a spontaneous rise in the body core temperature even without application of electricity which may be a reason for the typical temperature plateau after death.     

Post-mortem changes in skeletal muscle protease and creatine phosphokinase activity — A possible marker for determination of time of death

The pattern of change in activity of two enzymes in rat skeletal muscle during body storage after death has been determined. Myofibrillar protease activity was found to increase linearly with time of storage post mortem at room temperature but not at 4 °C. In contrast, creatine phosphokinase activity declines linearly with time, and again storage at 4 °C prevented the change in enzyme activity. Starvation of animals for 5 days or forced exercise prior to death did not markedly alter the rate of change in activity of the two enzymes, although creatine phosphokinase specific activity at time of death was higher in the starved and exercised rats as compared to control animals. A plot of the logarithm of protease/creatine phosphokinase specific activities ratio versus time post mortem yields a linear curve at room temperature. These observations offer a potential method for estimating time of death.     

The diagnostic significance of the quantitative glycogen content in cadaveric tissues in different types of death

The author developed a method for glycogen content determination in histological sections of the liver, heart and the skeletal muscles, stained according to Best, in case of death from ischaemic heart disease, acute ethanol intoxication, overcooling. Different variation limits of glycogen level in these kinds of death as compared to data in case of death from lethal mechanical injuries ("normal value") were determined.     

Supravital electrical excitability of muscles

A new method of postmortem electrical stimulation of muscles, measuring the force of the reaction against time, is presented. Preliminary investigations have yielded the following results: The maximum force of reaction in response to a definitive stimulation, measured by a sensitive force transducer, decreases in proportion to the post mortem interval. Using this method, the mechanical reactions of muscles by electrical stimulation can be demonstrated over a much longer postmortem period as these movements are visible. The duration of postmortem reaction of different muscles seems to be much more uniform than was previously assumed. Occasionally, reactions of the M. orbicularis oculi can be seen for the longest time. The basal muscular tonus changes relative to time. The time course of a single force reaction also changes relative to the postmortal interval: the reaction becomes slower. It has been theoretically established that measurement of influencing factors such as temperature and pH in the tested muscle will enable the time of death to be more precisely estimated.     

Estimating time of death from measurement of the electrical excitability of skeletal muscle.

Post-mortem contraction was measured using sensitive force transducers inserted into human muscle. The muscle was stimulated using rectangular impulses of 1 sec duration and known current intensity. After some time, a noticeable change of the muscular contraction occurred, from a two-peak to a one-peak shape. The maximum force of the muscular contraction using a stable current intensity decreased with time since death, but relaxation time increased. The decrease of the maximum force and the increase of the relaxation time were used as criteria for extrapolating the time since death in a random sample of 50 bodies. The calculated 95% limits of confidence were 2.85 h (decrease of the maximum force) and 2.7 h (increase of relaxation time) up to 13 hours post mortem. The calculated 95% limits of confidence were checked on an independent sample of 21 bodies and proved to be reliable.     

Postmortem decrease in brain temperature.

The postmortem decrease in central brain temperature in a small number of forensic cases is presented. Each case shows a simple exponential fall during the time of the measurements. The data reported by Brinkmann et al. (1978), when plotted in semilogarithmic coordinate system, also show--after an initial "plateau" of about 2 h--a strictly one-term exponential temperature fall for several hours post mortem. The curve of brain temperature fall allows conclusions about the time of death without considering clothing, body stature, and weight. The interval temperature measurements which are required may be obtained on the spot, and the calculations needed are very simple. The method, therefore, seems preferable to those depending on rectal temperature measurements.     

Estimation of Time of Death With a Fourier Series Unsteady‐State Heat Transfer Model

Abstract: The purpose of this study was to return to fundamental principles of heat transfer and derive a suitable model to establish a firm basis for constructing a postmortem human cooling curve. A Fourier Series Model was successfully applied to unsteady heat transfer within a wooden cylinder in controlled laboratory conditions. Wood has similar thermal diffusivity properties as human tissue. By manipulation of the model, sensitivity analyses were performed to observe the impact of changes in values of input variables. Variables of initial temperature of the cylinder and ambient surrounding temperature were shown to be very sensitive and have the most impact upon predictive results of the model. The model was also used to demonstrate the existence of an initial temperature plateau, which is often the subject of controversy in estimating time of death. Finally, it was demonstrated how the Fourier Series Model can be applied to estimate time of death for humans.     

The electric conductivity indices of the skeletal muscles in the dynamics of the posttraumatic period]

In order to determine the time of inflicting mechanical trauma, values of electric conduction of skeletal muscles were measured taking into consideration postmortem interval and temperature of an object tested. Electric conduction of traumatized and intact muscles was determined within 0, 6, 12, 24, 48 and 72 hr of posttraumatic period directly after death (the 1st series of observations) and in different postmortal periods. The results of investigations disclose presence of certain time-course changes in parameters of electric conductivity of skeletal muscles depending on time of posttraumatic period.     

超生反应阶段骨骼肌机械性损伤的形态学研究

对20例1．25～8．30hpm具有超生反应能力的尸检骨骼肌和17例10～24hpm和48～60hpm不具超生反应能力的尸检骨骼肌进行机械性损伤刺激的形态学系列对比研究。结果表明，经机械打击刺激后，具超生兴奋性的肌肉，受打击部位的肌纤维出现类似典型生前伤征象的形态学改变，而不具超生兴奋性的肌纤维仅出现被动的肌纤维断裂等非活性肌纤维改变。通过对超生形态学反应的形成机理进行探讨，为进一步研究超生形态学的作用提示了前景。