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).     

A line already drawn: the case for voluntary euthanasia after the withdrawal of life-sustaining hydration and nutrition

When life-sustaining hydration and nutrition is withheld from an incompetent and immobile patient like Terri Schiavo, death comes to the patient by dehydration within about two weeks. Americans should be permitted to arrange for euthanasia at that point, as opposed to merely dehydrating to death, and should be able to incorporate their desire for euthanasia into an advance directive. A state constitutional right of privacy could provide the legal avenue permitting effectuation of such a choice.     

Postmortem citalopram concentrations: alone or along with other compounds

Citalopram, an antidepressant whose use has become more widespread in Spain in recent years participates directly and indirectly in the lethal mechanism in voluntary and involuntary poisonings. There were 30 cases of autopsies in the Madrid region where citalopram and other psychoactive substances (psychotropic drugs, alcohol, opiates) were detected in the corpses. The postmortem citalopram levels in relation to the manner and mechanism of death were evaluated, and a significant difference between the toxic and nontoxic cases (p < 0.01) was found. We studied the citalopram blood levels alone and along with other psychoactive products, and these cases were then further divided into those where the compounds were at deadly levels and those which were not. We found a range of citalopram levels between 0.37 and 0.83 microg/mL in which some cases were associated with citalopram toxicity and others were not. Citalopram blood levels of less than 0.35 microg/mL did not lead to fatal poisoning when it was the sole substance detected.     

Y-chromosome STR system, Y-PLEX 12, for forensic casework: development and validation

The Y-PLEX 12 system, developed for use in human identification, enables simultaneous amplification of eleven polymorphic short tandem repeat (STR) loci, namely DYS392, DYS390, DYS385 a/b, DYS393, DYS389I, DYS391, DYS389II, DYS 19, DYS439 and DYS438, residing on the Y chromosome and Amelogenin. Amelogenin provides results for gender identification and serves as internal control for PCR. The validation studies were performed according to the DNA Advisory Board's (DAB) Quality Assurance Standards. The minimal sensitivity of the Y-PLEX 12 system was 0.1 ng of male DNA. The mean stutter values ranged between 3.76-15.72%. A full male profile was observed in mixture samples containing 0.5 ng of male DNA and up to 400 ng of female DNA. Amelogenin did not adversely affect the amplification of Y-STRs in mixture samples containing male and female DNA. The primers for the Y-STR loci present in Y-PLEX 12 are specific for human DNA and some higher primates. None of the primate samples tested provided a complete profile at all 11 Y-STR loci amplified with the Y-PLEX 12 system. Y-PLEX 12 is a sensitive, valid, reliable, and robust multiplex system for forensic analysis, and it can be used in human forensic and male lineage identification cases.     

Enhanced kinship analysis and STR-based DNA typing for human identification in mass fatality incidents: the Swissair flight 111 disaster

A bioinformatic tool was developed to assist with the victim identification initiative that followed the Swissair Flight 111 disaster. Making use of short tandem repeat (STR) DNA typing data generated with AmpFlSTR Profiler Plus (PP) and AmpFlSTR COfiler(CO) kits, the software systematically compared each available STR genotype with every other genotype. The matching algorithm was based on the search for: (i) direct matches to genotypes derived from personal effects; and (ii) potential kinship associations between victims and next-of-kin, as measured by allele sharing at individual loci. The software greatly assisted parentage analysis by enabling kinship evaluation in situations where complete parentage trios were unavailable and, in some situations, with distantly related relatives. Exclusion of fortuitous kinship associations (FKA) was made possible through the recovery at the disaster site of at least one remains for every sought-after victim, and was incorporated into the kinship software. The data from the 13 combined STR loci produced 6 and 23 times fewer FKAs when compared with PP alone and AmpFlSTR Profiler (PR) alone, respectively. Identification leads or confirmations of identification were obtained for 218 victims for which DNA reference samples (personal effects and kin) had been submitted. Confirmation of an inferred kinship association was sought through frequency and likelihood calculations, as well as corroborative data from other identification modalities. The use of a simple, yet powerful, automated genotype comparison approach and the use of megaplexes with high power of discrimination (PD) values extended considerably the identification capabilities in the case of the Swissair disaster. The DNA typing identification modality proved to be a valuable component of the large arsenal of identification tools deployed in the aftermath of this disaster.     

Systematic analysis of stutter percentages and allele peak height and peak area ratios at heterozygous STR loci for forensic casework and database samples

To assist the interpretation of STR DNA typing results from forensic casework samples containing mixtures, the range of heterozygous allele peak height and peak area ratios (HR) and stutter percentages (stutter %) for the loci comprised in the AmpFlSTR Profiler Plus (PP) kit were assessed on 468 database and 275 casework single source samples. Stutter % medians were similar for database and casework samples, ranging from 2% to 7%. The upper limit of the stutter value range was 16%, calculated as median +3 SD, although lower locus-specific values could be used. HR medians were 93 +/- 6.5% for database samples, 88 +/- 12% for casework samples. For casework samples, the maximum signal imbalance noted was 52%, calculated as median -3 SD. No significant difference was observed between peak height and peak area calculated values. This study shows the importance of selecting the proper reference database for the establishment of HR threshold values.     

Oxycodone intoxication in an infant: accidental or intentional exposure?

A case is presented of a 10 month old male who went into cardiac arrest at a local store. The infant subsequently expired and was autopsied at the Office of the Chief Medical Examiner, State of Maryland. The only remarkable finding was the detection of oxycodone in the postmortem specimens; the blood and liver oxycodone concentrations were 0.6 mg/L and 1.6 mg/kg, respectively. Oxycodone was identified and quantitated by gas chromatography-nitrogen-phosphorus detection and confirmed by full scan electron ionization gas chromatography-mass spectrometry. The medical examiner ruled that the cause of death was oxycodone intoxication, and the manner of death was homicide. The key toxicologic question in this case was whether or not it was reasonable for the infant to be exposed to oxycodone exclusively through breast milk or through an alternate source. It was concluded that, at best, there were serious concerns about the likelihood of drug exposure through consumption of breast milk.