Dating of the corpses

Synopsis

Medico-legal definition of death

The state of seems not not to be very well encircled by the legislation. If everyone recognizes that death is characterized by a decomposition of the body, it is states carrying out irremediably to this decomposition without the decomposition being installed; it is for example the case of brain death, the cardiac activity being present. Question morals, even religious arises then: does a person in this state have to be regarded as dead, which allows for example the taking away of body, or must it be regarded as alive, therefore maintained in life in an artificial way? Let us note that the dating of a corpse can estimate only the date from which the decomposition starts. In , gave a definition of death making it possible to solve the question. This definition is on the one hand a negative definition: an individual died if it does not present apparent signs of life like , , the activity . One agrees to regard death as the stop of the vital functions. In addition one finds a definition positive which supplements the preceding one: an individual died if it has on the level of sound macroscopic of the signs known as positive death. The positive signs of death are late, but their presence attests in an irrefutable way death. The subject is delicate as much than death does not occur in a way generalized on the unit of the body. All them does not die but not at the same time and all depends on the "type of death": at the time of one heart failure, the bodies do not die in the same order as in the case of a car accident having involved an irreversible cranial traumatism. It is important to specify that one distinguishes several types of dead: death , death , the death of, the death of. However the observation of the death of an individual is sometimes not sufficient. One thinks in particular of the observation of death within the framework of a police investigation. It is necessary to know to estimate the death of the victim to be able to bring evidence of the inculpation or innocence of the suspect. The criminal police force and collaborates thus between them. The objective of this article will be to define how one can date the death whereas their passage in a lethal state is not clearly defined. One will study the various methods of dating according to a chronology in two stages:

  • The phase postmortem early (until a few days after the death).
  • The phase postmortem average (up to one month).

Technique of dating of a corpse in early phase post-mortem

Estimate of the time post-mortem by thermometric methods

After the death, the stop of the phenomena ofhomeothermy involve a progressive equalization of of the body with that of its environment (in the moderate countries it will thus act generally of one cooling). Although this phenomenon is known of long date, its potential interest in the field of was identified only about the middle of XIXE century. Principal interest of cooling as a marker of the time post-mortem is that it acts of an easily quantifiable phenomenon, with the difference of the other cadaveric markers.

Modeling of cooling

Under the moderated climates, of on average joined that of the surrounding medium into 8 to 12 noon but the central temperature of the corpse requires with this intention a time two to three times more important. These observations carried out to a certain number of abusive simplifications according to which:

  • would be equalized with that of the ambient conditions of 24 hours.
  • The speed of cooling would be 1 °C per hour during the first 24 hours.

These simplifications rested on the idea that cadaveric cooling could be one of time. It is known today that it of it is nothing.

A second approach consists in using the laws of and to suppose that the heat flux is proportional to the difference in temperature between the body and the ambient air. This approach then makes it possible to model the fall of temperature by a function :

<maths>\frac{T_{corps} - T_{ambiant}}{37,2 - T_{ambiant}} = e^{-kt}</maths>

However this modeling does not appear satisfactory not confronted with the reality of the experiment. Indeed, one notes, without being able to explain it, that the fall of temperature is carried out in three phases:

Évolution de la température rectale en fonction du temps
Change of the rectal temperature according to time
  • A phase known as of initial thermal plate (duration from 0,5 to 3 a.m., with important interindividual variations): for this period and for reasons still badly known, of the corpse decrease very little; it results a first limitation from it from the thermometric method, because this one proves inoperative to go back a recent death going up with less than three hours.
  • An intermediate phase of fast decrease , semi-linear, which is that where the thermometric method proves most relevant to date death.
  • A final phase of slow decrease where of the body ends up being equalized very gradually with that of the ambient conditions. Starting from this phase, the thermometric method is not usable any more.

Doctor Claus Henssge, professor of forensic medicine at the university of Essen (Germany) sought to model the thermal decrease in the form of a variable Bi-exponential function according to weight's of the individual. It proposes following modeling then:

<maths>\frac{T_{corps} - T_{ambiant}}{37,2 - T_{ambiant}} = 1,25 e^{-kt} - 0,25e^{-5kt}</maths>

where K is a parameter depend on the mass M (in kg) of the individual:

<maths> K = \frac{1,2815}{M^{0,625}} - 0,0284</maths>

The observation of these two functions makes it possible to notice that

  • the derivative at time T = 0 of the temperature is null, which makes it possible well to model the initial stage.
  • The decrease is all the more slow as the mass of the individual is high.
Nomogramme de Henssge
Nomogram of Henssge

Like a medical examiner does not have always under the hand a scientific computer to determine T according to T, Claus Hengsse created a system of allowing to determine, according to the temperature of the body, the ambient temperature and the mass of the individual, the probable time of death. It is it nomogram of Henssge.

For the value found by the nomogram of Henssge, it will be necessary to apply corrective factors by holding account owing to the fact that the change of the temperature depends on many factors such as:

  • Characteristics specific to the body : initial temperature, age, possibly presence of clothing...
  • Conditions depending on the external medium : presence of wind or draughts, presence of moisture, variabililté of the outside temperature.

Practical use

On a scene of death, it is essential to measure central of the corpse as well as that of the environment (i.e. the temperature of ambient). Two measurements must be carried out at the same time with the same instrument, and the hour of measurement must be noted with precision. Almost always, the temperature of the corpse will be measured at the rectal level while knowing that this anatomical site can present problems when the victim could be the subject of sexual violences. The taking of temperature should never be carried out with one medical, because its range of temperatures is restricted too much, the instrument of reference being the electronic thermometer to , of high degree of accuracy and equipped with probe of a flexible or rigid penetration. The latter must be introduced from at least 10 to 15 cm into of the corpse to obtain a good estimate of the central temperature. When it is measured under adapted conditions, the temperature of the body must be regarded as one of best estimators time post-mortem during the first 24 hours.

This technique however presents a certain number of limitations:

  • It is valid only during the intermediate phase of the evolution of cooling, i.e. between 3 and 18 hours.
  • The thermometric method supposes that body at the time of the death was within the physiological limits (between 36,8 and 37,6 °C); one (met for example in the case of a death in an infectious context) or one handle-mortem (for example died found somebody of cold) can distort the estimates considerably, and must thus be studied each time information on the circumstances of death is available.
  • The equations of cooling also suppose that environmental remained appreciably constant for all the period post-mortem. That can be the case when the death occurs in heated or air-conditioned buildings, nevertheless problems arise in the case of bodies found in the external medium.

Determination of the time post-mortem by the thermometric method can in addition be skewed by a certain number of interfering factors of endogenous origin (cadaveric) or exogenic (environmental). The principal ones of these factors are:

  • Movements of, which accelerates the thermal losses by . For this reason, it is important to note if time is windy when the scene of death is located in outside, or if there are draughts when this one is located inside a dwelling.
  • of : the thermal losses are all the more important as the relative humidity of the air is high.
  • The presence of clothing : clothing plays the part of thermal and the cooling of the body will be all the more delayed that their thickness will be important (even notices for any other "coating" of the body: cloths, feather bed...).
  • Case of an immersed body : the thermal loss of the corpse is much faster in that in, and is still seen accelerated when the body is plunged out of running water.

The most practical method to estimate a time post-mortem by the thermometric method consists in using the normogramme of Henssge. But preceding modeling does not play that for a naked body in a calm air. It is thus often necessary to utilize elements of corrections which reduce or accelerates the cooling of a factor cf. If cf is higher than 1, the body cools more slowly. A factor cf lower than 1 indicates that the body will cool more quickly.

  • Naked body, calm air: Cf = 1,0
  • Little equipped body, calm air: Cf = 1,1
  • Moderately equipped body, calm air: Cf = 1,2
  • Warmly equipped body (more than 4 layers of clothing), calm air: Cf = 1,4
  • Very equipped body, very covered, reads: Cf = 2 to 2,4
  • Naked body, air moving: Cf = 0,75
  • Little equipped body, air moving: Cf = 0,9
  • Moderately equipped body, air moving: Cf = 1,2
  • Warmly equipped body, air moving: Cf = 1,4
  • Naked and wet body, calm air: Cf = 0,5
  • Little equipped body and wet clothing, calm air: Cf = 0,8
  • Moderately equipped body and wet clothing, calm air: Cf = 1,2
  • Warmly equipped body and wet clothing, calm air: Cf = 1,2
  • Naked and wet body, air moving: Cf = 0,7
  • Little equipped body and wet clothing, air moving: Cf = 0,7
  • Moderately equipped body and wet clothing, air moving: Cf = 0,9
  • Warmly equipped body and wet clothing, air moving: Cf = 0,9
  • Naked body in stagnant water: Cf = 0,5
  • Body little equipped in stagnant water: Cf = 0,7
  • Body equipped moderately in stagnant water: Cf = 0,9
  • Body equipped warmly in stagnant water: Cf = 1,0
  • Naked body in running water: Cf = 0,35
  • Body little equipped in running water: Cf = 0,5
  • Body equipped moderately in running water: Cf = 0,8
  • Body equipped warmly in running water: Cf = 1,0

It should however be become aware that this calculation can be only one estimate. the nomogram of Hengsse does not propose a fixed duration but a fork of estimate.

Many authors proposed alternative solutions to improve the precision of this technique:

  • Measure repeated or continues post-mortem during several hours.
  • Measure central by invasive means (introduction of probes at the level intrahepatic, intracerebral, etc.).

These methods have jointly to be difficult to put in?uvre in routine on a scene of death; moreover none of them truly showed its superiority compared to the thermometric method of reference.

Example

One finds a body in a pond. This one weighs 80 kg and its is 20 °C. Using data , one determines the last fifteen days the average temperature: one obtains, for the temperature of water, <maths>T_{\mathrm{moy}}=10 </maths>. On the nomogram, one bed 23 hours for the estimate, then the corrective factor is applied: since the body was found in stagnant, it is necessary to multiply the time estimated by 0,5.

One thus obtains <maths>0,5\times 23 = 11,5</maths> hours. The fork of reliability to 95% is, in this precise case, of approximately 4,5 H. what places the date of dead between 7h and 16h earlier.

The rigor mortis: a tool in the estimate of the early time post-mortem

rigor mortis (or rigor mortis) is enraidissement progressive of caused by transformations irreversible affecting muscle fibres during the phase post-mortem early. This state usually disappears when the putrefaction appears, i.e. at the end of two to four days according to circumstances'.

Explanation of the rigor mortis

Schéma d'une fibre musculaire
Diagram of a muscle fibre

Rigidity is characterized by a loss of of , and in particular of , caused by of myosine, one which is present there.

More precisely, it is due to the stopping of the pumps (thus of the provisioning of in energy) which involves an accumulation of Ca2+ in of the cells . By the means of this deterioration and by the loss of the sealing of the endoplasmic reticulum, the cytoplasmic concentration of Ca2+ increase. Under the action of this ion, bridges between the filaments of and of myosine are formed what involves the immobilization of .

The disappearance of rigidity is in connection with and the putrefaction which destroy the structure of the filaments of and of myosine as well as which links them.

Practical use

The rigor mortis affects the whole of of the organization: it begins with the nape of the neck then follows a downward walk towards the lower limbs, as the law of Nysten indicates it. Indeed, it touches initially the small muscles located in top of body then the more important muscles (in particular lower limbs) where it prevails what explains this downward walk.

  • Rigidity begins between 3 and 4 hours after the death, almost always on the level of the cervico-cephalic end (nape of the neck and mastiquateurs).
  • It reaches its maximum intensity between 8 and 12 hours.
  • It is maintained then between 12 and 36 hours.
  • Then it disappears gradually into two or three days, when the putrefaction appears.

In the event of artificial rupture, for example a displacement of the corpse, intervening less than 8 to 12 noon after death, rigidity can reappear; it is not the case when the rupture intervenes beyond this time (partner with other methods of dating, this consideration allows for example to note that the corpse at moved summer). This chronology is only indicative and actually one observes considerable interindividual variations according to ambient (like all the cadaveric phenomena, rigidity is all the more fast as the ambient temperature is raised and conversely), of a possible activity intense before death, of the importance of the musculature of the subject and the cause of the dead one:

  • Rigidity is faster in the event of convulsions handle-mortem, in certain toxic deaths (...), in , in the deaths preceded by a state by or when death occurs during efforts intense.
  • It is slower in certain deaths asphyxic (hanging, with ...), or at the time of massive.

The rigor mortis presents other limitations:

  • It can vary in intensity: thus, it is far from important at the old or émacié subject or at the time of anguishes prolonged (in this case, it is necessary to take care should not be confused with the stiffness due to ).
  • There is not instrument or of technique making it possible to quantify it in a precise way.

For these various reasons, the rigor mortis should never be used separately to try to determine the time post-mortem but must be exploited in the light of other methods of dating.

Cadaveric lividities

cadaveric lividities (or livor mortis) are a red colouring with purplished related to a passive displacement of towards the sloping parts of the corpse, which begins as of the stop from the flow from .

Explanation of cadaveric lividities

The process of appearance of cadaveric lividities begins as of death from the individual. Indeed:

  • makes drive it in the organization and its stop involves the stagnation of it.
  • After death, openings are formed in the wall of , consisted of cells endothéliales.
  • red globules escape then from the vessels, them D = 1,095 being higher than that of the blood plasma and other blood cells, ranging between 1,070 and 1,085.
  • , while accumulating, becomes visible by translucidity of , from where a modification of its colour which characterizes cadaveric lividities.

Practical use

Cadaveric lividities are distributed in a characteristic way on the corpse:

  • They appear initially on the neck and extend then to other areas from the organization around the fifteenth hour after the death.
  • They save the points of : thus, under the effect of , it of a lengthened victim accumulates, is immobilized and will become persistent under compressed of the lowest parts.

The speed of formation of lividities is variable. In a general way:

  • They are visible as from the second hour after death.
  • They become then gradually increasingly marked to reach the maximum of their intensity to the twelfth hour.

In addition, the mobility of lividities is also interesting:

  • They are initially erasable with : a support applied to a zone of lividity drives out it of and takes a paler colour compared to the neighbouring zones.
  • With the twelfth hour, and following the loss of sealing of the vascular walls, blood soaks interstitial fabric and itsupport applied to a zone of lividity cannot move blood any more. At this stage, lividities are known as fixed.

In the criminal businesses, lividities can thus indicate a possible change of position of the corpse, if their noted site does not correspond to that awaited. The colour of cadaveric lividities can give information on the cause of death. Lividities of colour red-carmine are typical of an intoxication with (<maths>\mathrm{CO}</maths>), whereas cyanosées lividities generally direct towards a asphyxic cause or a secondary death of with a pathology or .

Proportioning of potassium in the vitreous humour of the?il

Coupe sagitale de l'œil
Cut sagitale of the?il
Prélèvement de l'humeur vitrée contenue dans un œil de bœuf
Taking away of the vitreous humour contained in a?il of b?uf

The use of proportioning of contents in the humour vitreous of date of more than 25 years. It is a useful method but which, with it only, is hardly more precise than the clinical signs. This method rests on the following principle: when the organization ceases its activity, the cells of the wall lose their semi-permeability and consequently releases a part of the ions which they contain (in particular potassium). And more time passes more the content potassium increases. There cannot be possible contamination by the vitreous humour, because this one to be translucent must contain ions very little. The essential advantage of this method is that it is usable during a few days (up to one week) whereas the nonbiological methods are not it that during 24 to 48 hours maximum.

  • Taking away : the taking away is done by means of a syringe of an intramuscular needle, in the external angle of, by soft aspiration in order to avoid any contamination or . It must be carried out most precociously possible i.e. at the time of discovered body, before its setting in refrigeration.
  • Proportioning : by a laboratory accustomed (selective electrodes) after agitation and homogenisation.
  • : technique resting on a total proportioning of in a biological liquid, the conditions of conservation do not have practically any influence on the results.

The scientists could establish, the following formula based on more than 200 calibrations: between 18 and 20 °C, <maths>t=3,23\cdot K-8,2</maths>, <maths>t</maths> being the time post-mortem expressed in hours and <maths>K</maths> of in the humour vitreous in <maths>\mathrm{mmol}\cdot\mathrm{L}^{-1}</maths>. This formula is relatively vague, since sound reaches 9 hours. However it is rather simple to apply since it acts of a linear function of the potassium concentration. It is preferable to have the results of a calibration carried out in laboratory, in order to have an estimate of the time post-mortem more precise than that given by the formula. Under experimental conditions, it is weaker. coming from cellular does not have a linear increase. is a very important factor since it slows down considerably the increase in the quantity of potassium present in the vitreous humour.

Technique of dating of a corpse in average phase post-mortem

Putrefaction

putrefaction is the decomposition of organic under the dominating influence of bacteria lodged by the individual, especially those of , then of mycètes saprophytes and of the mineralizing bacteria which invade the corpse.

The putrefaction begins by:

  • Appearance of an abdominal green spot on the level of the right iliaque pit.
  • Appearance of an abdominal green spot on the level of the left iliaque pit.
  • Extension of these two spots who end up gradually gaining all the lower part of.

The various ones mycètes follow one another in given groups and this changes according to progressive deteriorations of which constitutes thus, at a given time, a habitat of election for certain species of mycètes and not for others. There are three successive waves:

  • At the first stage of the putrefaction colicative and gas, one finds only the species following: species.
  • At one more advanced period transformation of greases, follow one another: species.
  • Lastly, at the stage of the skeletal reduction, develop: species.

Putrefaction of the corpse due to bacteria and with mycètes saprophytes accentuating the deterioration started by, smooth of waste which the mineralizing bacteria will make return in the cycle of waste of the biosphere. Let us stress that all these modifications post-mortem and their succession are influenced, i.e. accelerated or delayed by many factors:

  • The volume of the corpse is important to consider, deterioration is faster for a small corpse for example
  • The age of the corpse.
  • Causes of death.
  • The discharge point.
  • External factors : seasons, conditions in particular and the degree , ventilation..., are as many points to be considered.

Medico-legal entomology

Realization of an entomological investigation

One collects a maximum of representatives of that one finds on the corpse and around this one, alive, dead like at various stages of development. One specifies the site, the date, the hour of the taking away, the state of the corpse, the conditions of taking away... The specimens thus taken are separate into two:

  • A part is preserved in.
  • The other is intended for under similar conditions with those of the environment ( and ) of the corpse and its vicinity.

They are identified insects that one finds, one determines:

  • The age stages .
  • Duration of incubation .
  • The time of arrival of these insects on the corpse.

By holding account of the environmental conditions, one can thus estimate the time thus postmortem corpse.

Types of arthropod which one finds on the corpses and their utility

The examination of allows an estimate of the time postmortem, a possible mobilization of the body as well as an identification of the place of the death. Best indicators among is them dipterous. Several types of arthropods can be on a corpse:

  • Arthropods necrophagous who nourish corpse.
  • Arthropods nécrophiles who nourish other preceding animal species i.e. the arthropods necrophagous.
  • Arthropods nourishing at the same time corpse and fauna present on the corpse, as it is the case of some hyménoptères and some coleopters.
  • Opportunist arthropods whose presence is not systematic for all the corpses but due randomly like the spiders for example. Those are thus not useful for the estimate of the time postmortem.
Method and condition of the taking away of insect on corpses

A minimum of material is essential with the taking away:

  • insects wheels require a net and adhesive paper of type "catch-fly".
  • Other insects a grip with racket, a flexible grip of entomology, a soft brush, bottles, labels of the pencils, one and one as well as conservatives.

This specific material supplements the material of protection and photography. The development of depends much on the conditions of the medium in which one finds them. One must thus measure:

  • The state of the body.
  • .
  • .
  • The exposure.
  • The microclimate and the local environment are also studied.

The conditions are not the same ones according to the place or the body is discovered

The fauna of the corpses to the free air

One counts in all and for all seven different squads, but only the three first allow a precise dating. The laying is generally done day and usually does not occur below 4°C.

  • The first section primarily consists of dipterous ( green, with checkerworks, blue...). It hardly arrives a few hours after death, and to 20 °C the larvae established in the corpse can reach the adulthood in 2 weeks.
  • The second section arrive after one month, attracted by the decomposition of . It is made up of sarcophagiens and disappears to the 6E month.
  • The third section appears between the 3E and 9E months and consist of dermestes (small coleopters) and sometimes of lépidoptères, attracted by the odor of rancid.

The other squads appear successively:

  • To the 10E month (section coryétienne).
  • Around 2 years (section silphienne).
  • When the body is not any more that dust, after 2 or 3 years, the seventh and eighth squads complete the work of their predecessors.
The fauna of the buried corpses

of the buried corpses is much less abundant than that of a corpse left with the free air since opportunities for to lay on this corpse is much less important. In this case, only will develop having been able to come into contact with the corpse. There are thus three possible cases:

  • The larvae were laid in the death chamber of the individual.
  • The larvae were laid in an area close to that in which the corpse rests.
  • The larvae come from the surface of the ground, if the corpse were buried with same the ground, or of the coffin out of wood in which the skin rests.

Appearance of on the body of late also depends on other circumstances:

  • Interval of time enters death and the burial.
  • Exposure time of the corpse in the death chamber.
  • Presence of a coffin.
  • Nature of the coffin (lead or wood).
  • Depth of the hiding.

present on a buried corpse consists of and of coleopters in majority. They appear there too successively on the corpse, which makes it possible to date death.

The fauna of the immersed corpses

The time roughly is determined postmortem grace the presence of some watery and certain species present usually on the body of a found corpse at the free air. One can quote them insects watery which, like theirs like the larvae of Trichoptères, serious damage with the immersed corpses inflicts. According to an experimental study made with The United States and bearing on the succession of the insects and the decomposition of the corpses of immersed, water limits the number of species present on the corpse, as well as necrophagous on the corpse. One finds overall a third of the species present on a corpse at the free air.

Arrival of the insects on the corpse and their proliferation

The human organism, once died, constitutes an enormous reserve in for bacteria like for insects. of body being protected more by , is then the prey of voracious necrophagous insects. The latter will be useful of the body of the individual deceased, in order to nourish itself, or to nourish their offspring. A few minutes after the death of the organization, it occurs of which is fermentative transformations (which are observed without the action of bacteria or of foreign agents at the organization). produced at the time of these reactions releases from the specific odors (not inevitably perceptible by), thus attracting the first insects who will lay theirs in the natural openings (, pores of ) and in the wounds. The laying is generally done day and usually below 4 °C does not occur. The appearance of the larvae can be done in less than one fifteen minutes after the laying. In the course of time, the deterioration of the corpse results in the release of odors, specific to a given period. Indeed, as the decomposition progresses, them of changes, as well as products and thus released odors. These new odors will push back the females attracted by the first odors. Other females then come, selectively, to colonize the corpse, and constitute squads. insect is attracted selectively what agrees by to him and it avoids the remainder.

Practical use

The composition of the squads, like their "working hours", can vary according to the factors which influence local entomological fauna and the processes of deterioration of the corpse:

  • The area and its geographical area.
  • The type of locality (city or countryside).
  • The type of site (in a dwelling or outside).
  • Data and (of which the season).
  • Conditions of storage of the body (with the free air, immersed, buried...).
  • The volume of the corpse.
Mouche bleue
Bluebottle

The decomposition of a corpse joins together a very diverse fauna ofinsects. One generally classifies them in four categories:

One counts in all and for all seven different squads, but only the three first allow a precise dating.

  • The first section primarily consists of dipterous ( green, with checkerworks, blue...). It hardly arrives a few hours after death, and at 20 °C them established in the corpse can reach the adulthood in two weeks.
  • The second section arrive at the end of one month, attracted by the decomposition of . It is made up of sarcophagiens and disappears in the sixth month.
  • The third section appears between the third and the ninth month and consists of dermestes (small coleopters) and sometimes of lépidoptères, attracted by the odor of rancid.

The other squads appear much more tardily:

  • The fourth section, or section coryétienne, arrives at the tenth month.
  • The fifth section, or section silphienne, approximately 2 years after the death.
  • The sixth and seventh squads complete the work of their predecessors at the end of two or three years, when the body is nothing any more but dust.

However this method is far from being perfect and for many entomologist, such Claude Wyss, it must be used with precaution. Indeed, according to the place where a person will die, them insects present will not be the same ones and a species of insect could very well be present in the first section then that elee is supposed to appear only with the fourth parce that individuals were close to the corpse at the time of its death and will thus have been able to feel it.

Development of of some according to time:
Fly domesticates (Musca domestica) Bluebottle (Calliphore vicina) Green fly (Lucilia caesar) Black fly (Sacrophaga carnaria)
0 (laying) ?ufs ?ufs ?ufs Larvae
2 days Blossoming (2 mm) Blossoming (2 mm) Blossoming (2 mm) Blossoming (2 mm)
3 days Larva (3 mm) Larva (5 mm) Larva (3 mm) Larva (5 mm)
4 days Larva (4 mm) Larva (7 mm) Larva (3 mm) Larva (8 mm)
5 days Larva (6 mm) Larva (10 mm) Larva (3 mm) Larva (10 mm)
6 days Larva (7 mm) Larva (13 mm) Larva (3 mm) Larva (13 mm)
7 days Larva (8 mm) Larva (13 mm) Larva (3 mm) Larva (15 mm)
8 days Pupaison (5 mm) Pupaison (9 mm) Pupaison (6 mm)
10 days Pupaison (10 mm)
14 days Adult
18 days Adult

Note:

  • of lasts between 12 noon and 24 H when ambient borders 25 °C; it is lower than 12 H if it is worth approximately 15 °C.

Note:

  • If a cold corpse is discovered without fauna in a place where is present, that indicates that the body was preserved in an isolated place, all the more if the body is at the beginning of autolysis.
  • If a corpse only comprises , then the phase post-mortem than 48 H is lower.
  • If the corpse is in process of deterioration and comprises only?ufs, then the body was transported or deposited on the spot since less than 48 H.
  • If a corpse comprises empty, that is a consequence of arrived of at least a cycle of dipterous the duration is of more than 12 days with 22 °C, of more than 14 days to more than 20 °C and of more than 19 days with 18 °C.

Determination of the temperature in the evaluation of the age of the insects

To proceed to the determination of the age of found on the corpse (and thus with the determination of the moment of dead), it is first of all necessary to know average daily of the site on which they were found: a statement of the temperatures (carried out daily by ) is thus necessary, if possible on several stations close to the site. But that is not still enough to have an average temperature of the site, this one being able to be different from that given by the stations: also one will take care to calculate the difference <maths>\theta</maths> of temperature by comparing that of the weather site and data lasting a score of days.

Determination of the date of laying

So that a species necrophagous can develop?uf with the perfect insect, it needs a sum of temperature specific to the species. This sum is calculated by adding the averages with temperature per day, less the index also specific to the species. When the sum is reached, it corresponds to the day of laying of the species.


The work of dating of the death is a tiresome task. The problem to date the moment from which death starts does not solve using a method miracle. The resolution of this problem is the?uvre agreement between several results produced by distinct methods of dating. These methods call at the same time upon the examination of body in itself but also with the observation of the action of on this one. Only the pooling of the dates brought by the various types of dating allows a dating of most precise. This dating and its precision depend on two factors which are the time and the place of stay of the body. However, always within the framework of a judicial enquiry, this work of dating is sometimes not a sufficient work. It is necessary sometimes to carry out as a preliminary an identification to be able to replace the victim within the framework of the investigation, (i.e. not to be based on evidence distort to judge a man), which proves very often difficult. Indeed, the body is sometimes in a rather important state of deformity (inflated within the framework of one drowned, or in an extreme state of decomposition) which returns this work of often difficult identification. The dating is not then of any utility if the victim is not identified. This problem of the identification is a problem which completely goes hand in hand with the dating, and it is a subject which it would be necessary to cover in order to perfect the knowledge brought by this talk.

Bibliographical orientation

  • Marcel Leclercq (1978). Entomology and Forensic medicine. Dating of death. Masson (Paris), Collection of forensic medicine and medical toxicology : 100 p.
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