AN APHORISM

There is an aphorism in medical science which says: "You see what you look for; you look for what you know." It can work positively or negatively. If you know something exists but is hidden from view, you may be able to espy clues that thereafter will lead you to it. Thus, discoveries in diagnostic method may be made. On the other hand, if you know something exists in some instances and generalize it to be of significance in all, you may be right--or you may gravely mislead yourself and others.

Williams, Greer. The Plague Killers. Charles Scribners Sons, New York: 1969.

PECULIAR SUICIDE

The September 2012 issue of Forensic Science, Medicine, and Pathology contains an interesting article by Hejna, et al., analyzing a case of complex suicide. The article defines complex suicide as one "in which more than one suicide method is applied either simultaneously or successively (one after the other)" and distinguishes complex suicides by two variations: planned, where two or more methods of suicide are combined simultaneously; and unplanned, where a second method of suicide is attempted to compensate for some unsatisfactory aspect of the first, i.e. unbearable pain, or inadequate severity.

This particular case was an instance of planned complex suicide, with the 39 year-old victim employing both a firearm and hanging. While this combination tends to be the most common in planned complex suicides, what makes this case salient is the use of a black-powder derringer. In what was likely an attempt to improve lethality, the gun was loaded with a powder charge far exceeding manufacturer specifications. This resulted in instantaneous death and atypical markings circumscribing the ballistic entrance wound. The effectiveness of the shooting rendered the secondary method of suicide ineffectual, as evidenced by the lack of indicators which are normally present in hanging deaths (such as bleeding into the intevertebral discs).

Hejna, et al. conclude with five key points for forensic investigators to take away from this case:

"1. The combination of hanging and gunshot injury is the most common arrangement involved in primary complex suicides. 

2. Injuries and fatalities resulting from the use of black powder handguns are relatively rare compared to other firearms. 

3. Black powder weapons produce entrance wounds with extensive sooting and powder tattooing (in close range and intermediate range shooting). 

4. The wounds from black powder firearms may have a characteristic sulfurous odor and the soot deposits may have a yellowish color. 

5. The atypical morphology of the entrance wound with extensive back spatter in this presented case was conditioned by the excessively short barrel of the derringer, a higher amount of black powder charge and by artificial incision of the projectile ogive."

 View of the victim as found, with prominent atypical entrance wound. [Hejna, Fig. 2]

"The handgun used– black powder muzzle loading doublebarreled derringer." [Hejna, Fig. 6]

Hejna, Petr; Šafr, Miroslav; Zátopková, Lenka; Straka, Luboš. Complex suicide with black powder muzzle loading derringer. Forensic Science, Medicine, and Pathology (2012) 8: 296-300. 

GREULICH-PYLE APPLICABILITY

The May 2012 issue of the Journal of Forensic Sciences has an article assessing the Greulich-Pyle method of skeletal age estimation. The study, by Cantekin, et al., analyzed left hand/wrist roentgenograms (x-ray photographs) for a sample of 767 Caucasian eastern Turkish sub-adults, aged 7 through 17, with known chronological age and gender. Although some unacceptably high standard deviations occurred in individual age groups, the difference between bone age mean and chronological age mean for males and females was not statistically significant. These findings reinforce the utility of GP estimation.

"FIG 1--Scatter plot of bone age versus chronological age in girls"

 "FIG 2--Scatter plot of bone age versus chronological age in boys"

Bone Age Assessment: The Applicability of the Greulich–Pyle Method in Eastern Turkish Children
J Forensic Sci, May 2012, Vol. 57, No. 3 doi: 10.1111/j.1556-4029.2011.02035.x
Available online at: onlinelibrary.wiley.com

SALIVA AS A PREDICTOR OF AGE

Promising research now shows that DNA Methylation of human saliva can be utilized to predict a person's age with a modest degree of accuracy. No doubt the technique will improve with refinement and ongoing technological advances. Inferential methods like this are invaluable, because they allow forensic investigators to build a suspect's profile without having to rely on database matches (as is the case with fingerprints, DNA, etc.).

Read a summary of the research here:

http://www.popsci.com/science/article/2011-06/saliva-science-new-forensics-tool-can-determine-age-suspects-spit

Then check out the genuine research publication on PLoS ONE:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0014821

ABSTRACT:

From the moment of conception, we begin to age. A decay of cellular structures, gene regulation, and DNA sequence ages cells and organisms. DNA methylation patterns change with increasing age and contribute to age related disease. Here we identify 88 sites in or near 80 genes for which the degree of cytosine methylation is significantly correlated with age in saliva of 34 male identical twin pairs between 21 and 55 years of age. Furthermore, we validated sites in the promoters of three genes and replicated our results in a general population sample of 31 males and 29 females between 18 and 70 years of age. The methylation of three sites—in the promoters of the EDARADD, TOM1L1, and NPTX2 genes—is linear with age over a range of five decades. Using just two cytosines from these loci, we built a regression model that explained 73% of the variance in age, and is able to predict the age of an individual with an average accuracy of 5.2 years. In forensic science, such a model could estimate the age of a person, based on a biological sample alone. Furthermore, a measurement of relevant sites in the genome could be a tool in routine medical screening to predict the risk of age-related diseases and to tailor interventions based on the epigenetic bio-age instead of the chronological age.

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ADIPOCERE

From Lerner [1]:

Also known as "grave wax," adipocere (from the Latin, adipo for fat and cera for wax) is a grayish-white postmortem (after death) matter caused by fat decomposition, which results from hydrolysis and hydrogenation of the lipids (fatty cells) that compose subcutaneous (under the skin) fat tissues.

Although decomposition of fatty tissues starts almost immediately after death, adipocere formation time may vary from two weeks to one or two months, on average, due to several factors, such as temperature, embalming and burial conditions, and materials surrounding the corpse. For instance, the subcutaneous adipose (fatty) tissue of corpses immersed in cold water or kept in plastic bags may undergo a uniform adipocere formation with the superficial layers of skin slipping off.

Several studies have been conducted in the last ten years to understand and determine the rate of adipocere formation under different conditions. Other studies also investigated the influence of some bacteria and chemicals, present in grave soils, in adipocere decomposition. Although this issue remains a challenging one, the purpose of such studies is to establish standard parameters for possible application in forensic analysis, such as the estimation of time elapsed since death when insect activity is not present. In forensics, adipocere is also important because preserved body remains may offer other clues associated either with the circumstances surrounding or the cause of death. The ability of adipocere to preserve a body has been well illustrated in exhumed corpses, even after a century.

Adipose cells are rich in glycerol molecules and are formed by triglycerols (or triglycerides). Bacterial activity releases enzymes that break these triglycerides into a mixture of saturated and unsaturated free fatty acids, a process known as hydrolysis. In the presence of enough water and enzymes, triglycerol hydrolysis will proceed until all molecules are reduced to free fatty acids. Unsaturated free fatty acids, such as palmitoleic and linoleic acids, react with hydrogen to form hydroxystearic, hydroxypalmitic acids and other stearic compounds, a process known as saponification, or turning into soap.

This final product of fat decomposition, or adipocere, can be stable for long periods of time due to its considerable resistance to bacterial action. This resistance allows for slower decomposition of those areas of a corpse where adipose tissues are present, such as cheeks, thighs, and buttocks. When a corpse is exposed to insects, however, adipocere probably will not be formed, as body decomposition will be much faster because of the insects' action. Animal scavenging of a dead body will also prevent adipocere formation.

Also worth a read is Ruttan and Marshall's 1917 piece,

The Composition of Adipocere.




NOTES:


1. "Adipocere." World of Forensic Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. Gale Cengage, 2006. eNotes.com. 2006. 16 Sep, 2010
adipocere>

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CSI: Kentucky

A fun article about forensic anthropologist Emily Craig:

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ZIP GUN SUICIDE

This guy went to a lot of trouble to off himself. No doubt there are dozens of more-convenient ways to commit suicide. Of course, had this been merely your average handgun-to-the-head scenario, it probably wouldn't warrant much attention here.

An Unusual Zip Gun Suicide—Medicolegal and Ballistic Examination (Full .PDF Journal article)

ABSTRACT: Home-made guns are imitations of typical firearms and usually have handgun characteristics. This article presents an unusual case of a suicide carried out by means of a fatal gunshot wound to the head using a home-made zip gun. A 49-year-old male, with a history of paranoid psychosis was found dead in the dwelling place of a family house. The investigation at the crime scene did not lead to suspicion of a gunshot wound because of the unusual nature of the firearm used. A medical examiner diagnosed an opened head injury as the primary cause of the victim’s death. The autopsy findings provided immediate grounds for further inspection of the crime scene. Subsequently, a simple zip gun, which had been overlooked during the scene investigation, was discovered. An undeformed projectile recovered from the victim’s head was consistent with the use of the home-made firearm. Following the completion of the investigations and autopsy, the death was classified as a suicide.

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ACCIDENTAL STRANGULATION

I must admit to harboring a personal fear of this particular type of accident. I grew up on a farm and also spent some years in a factory, working daily around heavy industrial machines. There were always horror stories circulating, most involved an article of clothing becoming stuck in a mechanized part and dragging a person towards inevitable mutilation or death. Accidents involving mechanical equipment happen fast, and machines--being, well, machines--are utterly unforgiving.

Accidental Ligature Strangulation by an Ironing
Machine: An Unusual Case (Full PDF Journal article)

ABSTRACT: In this paper, we present a case of a 53-year-old woman who had her headscarf catch on the cylinder ironing machine in the laundry of the hospital where she worked. The hospital workers found the woman dead with her head stuck to the ironing machine. After the death scene investigation and autopsy were completed, it was determined that the death occurred as a result of accidental ligature strangulation. Accidental ligature strangulation in which an article of clothing is caught in such an electrical machine and strangles the wearer is very rare. This case highlights the fact that these kinds of machines can be hazardous to work around and that increased safety measures should be taken to insure worker safety; additionally, the people who use these machines should be educated on the potential hazards.

EVIDENCE OF BLUNT FORCE IMPACT ON FABRICS

I've been reading some fascinating and extremely well-written journal articles regarding the forensic evidence of violent crime left on clothing. The following is excerpted from Daroux, et al. [1]

ABSTRACT:
Blunt force assault is a growing issue worldwide. In New Zealand, recorded cases of grievous blunt force assault increased steadily from 1011 in 1999 to 2139 in 2008 [2]. In many cases of blunt force assault victims are struck on parts of their body covered by clothing, yet the use of damage to apparel as forensic evidence largely appears to have been overlooked. The current research investigated blunt force impact
(BFI) damage in common apparel fabrics and the effects prior and post-laundering had on this damage. Two 100% cotton fabrics (single jersey knit, bull drill) were impacted as single and double layers using an impactor representative of a hammer face, the force transmitted through specimens was measured and impulse calculated. Impacting and laundering were completed cumulatively to establish the effects of impact damage on new, dimensionally stable (laundered 6 times) and aged fabrics (laundered up to 30 times), and the effects of laundering on impacted specimens. BFI left recognisable patterns of damage in specimens, although the extent of this damage varied. Laundering after the impact event altered the visible and microscopic damage. Laundering previously impacted fabrics produced holes in some specimens and some fibres exhibited failure characteristic of blunt force impact.

Fig. 5. Typical examples of fibre failure: (a) impacted, not laundered; b–d impacted then laundered fibres (b = example of fibre retaining flattened appearance, little fibrillar separation after laundering, c and d = fibres regained more three-dimensional appearance; c = short, uneven break, perpendicular to fibre axis, d = examples of messy, bulbous and collapsed fibre ends after laundering).

5. Conclusions
BFI can cause recognisable damage in apparel fabrics. Laundering apparel fabrics prior to impacting did not significantly alter the visible damage. Laundering apparel fabrics after impacting did not generally destroy evidence of BFI damage, but rather altered the damage. BFI damage to fabrics varied considerably due to other variables investigated, i.e. fabric structure, number of layers. Further research is required to develop comprehensive knowledge regarding BFI damage in apparel fabrics. Of particular importance would be consideration of incorporating an underlying human
tissue simulant, as fabric damage due to BFI is likely to be significantly affected by the underlying substrate. Different methods can be used to compare BFI damage. The most effective method investigated in this work, but one which needs to be
interpreted with care was SEM.

SOURCES:

1. Daroux, F.Y., Carr, D.J., Kieser, J., Niven, B.E., Taylor, M.C. (2010). Effect of laundering on blunt force impact damage in fabrics. Forensic Science International Vol. 197 (21-29).

2. Statistics New Zealand, New Zealand recorded crime tables, available online at
http://www.stats.govt.nz (14.02.08). [This is a direct reference from the journal article.]

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STRENGTHENING FORENSIC SCIENCE

A recent (2009) report by the National Academy of Sciences (PDF):

Strengthening Forensic Science in the United States: A Path Forward

If nothing else, I'd recommend chapters three through six as essential reading. The Federal Rules of Evidence and related case law covered in Chapter Three are relevant to every United States citizen. The purpose, method, and scope of science is misunderstood by far too many, and Chapter Four provides a great resource towards which the uninformed might be directed (this also ties in with law, insofar as jury instruction and the judge as "gatekeeper" are concerned). Chapter Five is a useful primer/history of forensic science, but is likely redundant for anyone who has taken an introductory forensic anthropology class. Chapter Six is essentially a plea for greater research, more rigorous standards/practices, and greater autonomy for science laboratories.

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