Does sexual dimorphism in facial soft tissue depths justify sex distinction in craniofacial identification?

Separation of male and female soft tissue depths into discrete groups for craniofacial identification implies that males and females differ enough from each other, with respect to this application, for this distinction to be useful. In this study, previously published soft tissue depth data were analyzed for sex separation. It was found that the variation within each sex was large while the variation between the sexes was small. Often the value of two standard deviations of the measurement for either sex was larger than the difference displayed between the means of each sex. Furthermore, opposite sex overlap in regions defined to be close to the male or female mean were found to be large and the amount of variance explained by sex was small (less than 6% on average). These results indicate that while male and female means at single craniofacial landmarks may differ slightly, and even at statistically significant levels, individual male and female soft tissue depths are often the same or very similar. On average, soft tissue depths of the face do display some sexual dimorphism but it is not marked and of little practical meaning for craniofacial identification where a single individual must be independently considered. Thus, there is little use in separate reporting of data for males and females and data should be combined to increase sample sizes.     

Postmortem non-invasive virtual autopsy: death by hanging in a car

A body was found behind a car with a noose tied around its neck, the other end of the rope tied to a tree. Apparently the man committed suicide by driving away with the noose tied around his neck and was dragged out of the car through the open hatchback. postmortem multislice-computed tomography (MSCT) and magnetic resonance imaging (MRI) indicated that the cause of death was cerebral hypoxia due to classic strangulation by hanging, and not due to a brainstem lesion because of a hang-man fracture as would be expected in such a dynamic situation. Furthermore, the MRI displayed intramuscular haemorrhage, bleeding into the clavicular insertions of the sternocleidomastoid muscles and subcutaneous neck tissue. We conclude that MSCT and MRI are useful instruments with an increased value compared with 2D radiographs to augment the external findings of bodies when an autopsy is refused. But further postmortem research and comparing validation is needed.     

Forensic case profiling aspects on multiple homicides from the Cologne-Bonn metropolitan area 1985-2000

The medicolegal and subsequent criminologic interpretation of forensic and pathological findings in cases of homicide makes up an important tool of case profiling. In a retrospective study of 26 cases of "multiple homicides" involving 31 perpetrators (30 males, 1 female, mean age 33.5 years) and 73 victims (33 males, 40 females, mean age 36 years, 68 fatalities, 5 survivors), autopsy reports and prosecution authorities' files were investigated with regard to individual characteristics of victims and offenders, circumstances as well as mode of commitment. The major aim of this study was to comprehensively elucidate and characterise relevant forensic and criminologic features, which may gain importance for forensic case profiling. Forty-six victims were found in the close social environment of the perpetrator and 45 homicides were committed either in the victim's, the perpetrator's or the shared domicile. The main motives included concealment of a crime (n=13), personal conflicts/domestic arguments (n=7) and greed (n=12). The relevant injuries with regard to the cause of death were attributable to sharp force (n=13), blunt force (n=7), gunshot wounds (n=24), ligature strangulation (n=3), smothering (n=5), fire/carbon monoxide (n=4) and combined impacts (n=11). In 15 cases, so called defence injuries were found. In 5 victims a post-mortem blood alcohol concentration >1.5 g/l was determined. In six perpetrators, a severe psychiatric impairment of juridical responsibility was ascertained (Section 20 German criminal code, n=2, psychosis; Section 21 German criminal code, n=4, acute alcohol intoxication). As far as conviction data were available, 27 crimes were juridically assessed as murder, 12 as manslaughter and one as bodily harm with fatal consequences.     

Medicolegal aspects of witnessed suicide due to gunshot to the head. II. Legal medicine aspects and examination of the firing hand

The second part of the paper on suicides by gunshots to the head in the presence of witnesses focuses on relevant morphological autopsy findings such as entrance site, signs of close range or contact shots, bullet path etc. and also discusses selected aspects of ascertaining gunshot residues. For the identification of the shooter an integral medicolegal assessment of all the facts including the investigation results and the autopsy findings is essential. However, the morphological findings alone do not allow safe diagnosis, as for example in a homicide the temporal region, which was affected in all our cases, may have been deliberately chosen by the perpetrator as a localization typical of suicide. Thus methods to ascertain gunshot residues on the firing hand (by means of adhesive films and the polyvinyl-alcohol collection method--PVAL) are of great practical importance. In seven cases adhesive films and/or the polyvinyl-alcohol collection method were used. In one case the gunshot residues (GSR) were analysed by means of tape lifts and subsequent scanning electron microscopy (SEM). It was found that especially the combined application of topographical (adhesive tape/PVAL) and cumulative (SEM) methods allowed for the doubtless identification of the shooter, thus usually confirming the suicide. By the example of one case it is demonstrated that without the immediate collection of evidence at the scene objective reconstruction of the event becomes impossible. On the basis of the reported cases recommendations are finally given for a differentiated approach in the medicolegal evaluation of alleged witnessed suicide by gunshot (to the head).     

Analysis of 1989-1999 homicide crimes in the catchment area of the Bonn Institute of Forensic Medicine with reference to selected aspects

195 cases of homicide, grouped according to juridical assessment, were retrospectively analysed with regard to individual characteristics of perpetrators and victims, circumstances, and mode of commitment. The involvement of underage victims and perpetrators as well as differences between the urban and rural areas studied were taken into special consideration. To summarise, the majority of the offences studied was carried out by a male perpetrator with a mean age of 35 years driven by personal motives or greed in his immediate vicinity and affected family members or close acquaintances. The fatal injuries were mainly attributable to sharp or blunt force. With regard to killings of children, a higher prevalence of female victims and male assailants, emotional motives and an even higher importance of the social vicinity were found. Particularly in victims younger 12 years of age, manual modes of commitment without application of any tools were predominantly encountered. The comparison of urban and rural areas revealed a higher homicide rate in municipal areas especially of offences with a loose relationship between victims and assailants (greed, sexual assault). In contrast, rural areas exhibited higher rates of bodily harm with fatal consequences as well as offences by highly intoxicated assailants.     

Predicting mouth width from inter-canine width--a 75% rule

It has been suggested that inter-canine width plus 57% of the cumulative distance between the lateral aspect of the canines and the pupil centers can be used to estimate mouth width. Evidence also suggests that the distance between the medial irises approximates actual mouth width fairly well. However, these soft tissue prediction guidelines are limited because they rely on accurate medio-lateral positioning of the pupils within the orbits, for which no systematic empirical evidence appears to exist at this stage. It would, therefore, be more appropriate to use only known hard tissue landmarks in mouth width prediction. This study reports the results of using inter-canine width as a percentage of mouth width for its prediction. This method seems favorable in comparison to the other guidelines because it is as accurate, uses known hard tissue landmarks, and does not rely on assumptions concerning pupil location. Estimating mouth width by using the canines alone, therefore, seems the best guideline to use in facial approximation techniques, at least given knowledge existing at this stage.     

Building faces from dry skulls: are they recognized above chance rates?

Methods of facial approximation have successfully aided the identification of deceased individuals. Successes may be due to either accurate facial approximation techniques or chance. This study aims to determine if any of 16 facial approximations, built using standard techniques, are sufficiently accurate to produce correct identifications of target individuals above chance. Four skulls were approximated using four commonly used methods of facial approximation. The resulting 16 facial approximations were judged by 37 assessors of varying ages. Assessors attempted to identify the target individual of each facial approximation from a face pool of ten photographed faces. Only one facial approximation resulted in true positive identification rates above chance at statistically significant levels. It is concluded that it is rare for facial approximations to be sufficiently accurate to allow identification of a target individual above chance. Since 403 incorrect identifications were made out of 592 identification scenarios, facial approximation should be considered to be a highly inaccurate and unreliable forensic technique. These results suggest that facial approximations are not very useful in excluding individuals to whom skeletal remains may not belong. Evidence from this experiment supports suggestions by others that facial approximation should be used in forensic science when all other methods of identification have failed and only to provide tentative identification.