Selective detection of trace nitroaromatic, nitramine, and nitrate ester explosive residues using a three-step fluorimetric sensing process: a tandem turn-off, turn-on sensor

Detection of trace quantities of explosive residues plays a key role in military, civilian, and counter-terrorism applications. To advance explosives sensor technology, current methods will need to become cheaper and portable while maintaining sensitivity and selectivity. The detection of common explosives including trinitrotoluene (TNT), cyclotrimethylenetrinitramine, cyclotetramethylene-tetranitramine, pentaerythritol tetranitrate, 2,4,6-trinitrophenyl-N-methylnitramine, and trinitroglycerin may be carried out using a three-step process combining "turn-off" and "turn-on" fluorimetric sensing. This process first detects nitroaromatic explosives by their quenching of green luminescence of polymetalloles (lambda em approximately 400-510 nm). The second step places down a thin film of 2,3-diaminonaphthalene (DAN) while "erasing" the polymetallole luminescence. The final step completes the reaction of the nitramines and/or nitrate esters with DAN resulting in the formation of a blue luminescent traizole complex (lambda(em) = 450 nm) providing a "turn-on" response for nitramine and nitrate ester-based explosives. Detection limits as low as 2 ng are observed. Solid-state detection of production line explosives demonstrates the applicability of this method to real world situations. This method offers a sensitive and selective detection process for a diverse group of the most common high explosives used in military and terrorist applications today.     

Fourier-transformed infrared breath testing after ingestion of technical alcohol

The study aim was to evaluate the feasibility of a Fourier-transformed infrared (FT-IR) analyzer for out-of-laboratory use by screening the exhalations of inebriated individuals, and to determine analysis quality using common breath components and solvents. Each of the 35 inebriated participants gave an acceptable sample. Because of the metabolism of 2-propanol, the subjects exhaled high concentrations of acetone in addition to ethanol. Other volatile ingredients of technical ethanol products (methyl ethyl ketone, methyl isobutyl ketone, and 2-propanol) were also detected. The lower limits of quantification for the analyzed components ranged from 1.7 to 12 microg/L in simulated breath samples. The bias was +/-2% for ethanol and -11% for methanol. Within-day and between-day coefficients of variation were <1% for ethanol and <4% for methanol. The bias of ethanol and methanol analyses due to coexisting solvents ranged from -0.8 to +2.2% and from -5.6 to +2.9%, respectively. The FT-IR method proved suitable for use outside the laboratory and fulfilled the quality criteria for analysis of solvents in breath.     

The Utility of the Samworth and Gowland Age‐at‐Death “Look‐up” Tables in Forensic Anthropology*

Abstract: Accurate age‐at‐death estimates are crucial to forensic anthropologists when onstructing biological profiles aimed at narrowing a missing‐persons list and to allow for timely and efficient identification of an unknown victim. The present contribution evaluates the utility of three new age‐at‐death estimation techniques recently proposed by Samworth and Gowland (2007). Results indicate that, in the samples under study, the Samworth and Gowland estimates from the pubic symphysis and auricular surface perform similar to alternate phase methods. The combined method does not appear to further enhance either the precision or the accuracy of the single pubic symphysis age‐at‐death estimate. In conclusion, these new methods seem to be more robust to distribution deviations than originally proposed by Samworth and Gowland (2007). They are therefore suitable for immediate and reliable forensic usage in the United States and worthy of further research for their use in North American forensic contexts.     

Quantitative Analysis of Gamma‐Hydroxybutyrate at Endogenous Concentrations in Hair using Liquid Chromatography Tandem Mass Spectrometry

Abstract: A method capable of quantifying endogenous concentrations of gamma‐hydroxybutyrate (GHB) in human head hair was developed and validated using liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS). Hair was digested under alkaline conditions, and GHB was isolated using liquid–liquid extraction. LC/MS/MS was performed using atmospheric pressure chemical ionization in the negative mode, multiple reaction monitoring, and deuterated internal standard (GHB‐D₆). Linearity was observed between 0.1 and 100 ng/mg GHB (R² = 1.000). The limits of detection and quantitation in human hair were 0.2 and 0.4 ng/mg, respectively. Accuracy at 2 ng/mg and 10 ng/mg was determined to be 97% and 94%, and intra‐assay CVs at these concentrations were 5.2% and 7.4% (n = 4). Beta‐hydroxybutyrate (BHB), alpha‐hydroxybutyrate, gamma‐butyrolactone, and 1,4‐butanediol did not produce an interference, and there was negligible ion suppression or enhancement from the matrix.     

Determining the Source of Equine Bloodstains by Dinucleotide Repeats*

Abstract: A novel multiplex of independent dinucleotide tandem repeat (DTR) loci was previously described that is capable of not only discriminating human and equine DNA, but of identifying a single equine source. We report a case in which a bloodstained syringe and two needles were found during inspection of a barn by inspectors of the Pennsylvania Racing Commissions. Using the multiplex and single‐locus detection, all 21 equine DTR markers were detected in a suspect horse and two evidence samples, indicating the evidence samples came from the suspect animal. Only six markers were detected in the third evidence sample because the volume of blood was limited. Following whole‐genome amplification and single‐locus PCR, the third evidence sample detected a total of 17 markers and the likelihood of identity (probability from suspect horse/probability from a random pacer) was 7.0 × 10⁶. The DTR multiplex has some technical limitations, but it is already practical for casework.     

An Autopsy Case in Which Self‐Bloodletting Via a Cervical Blood Access Led to a Fatal Outcome*

Abstract: A 48‐year‐old woman was found dead on a chair in her living room. She had received dialysis every day because of chronic renal failure for the past 15 years. On a table beside her, there was a mirror and 10‐mL syringe on a napkin. A stopper was out of place in a portion of a three‐way blood access tube established in the right cervical region, and blood coagulation was noted in the lumen. There was a bloodstained measuring cup on the floor. Autopsy findings included a large number of shunt traces in the bilateral infraclavicular fossae and upper limbs, as well as the cervical blood access terminal reaching the right atrium via the internal jugular vein to superior vena cava. Various organs showed anemia. Neither a fatal lesion nor injury was noted in the main organs. Therefore, this patient may have committed suicide by self‐bloodletting via a cervical blood access.     

Murder Followed by Suicide: A Newspaper Surveillance Study Using the New York Times Index

Abstract: Murder–suicide is a relatively uncommon event but as reported by the New York Times, it has occurred and continues to occur yearly. Previous research has indicated that those who commit murder–suicides tend to be men, are in or have been in an intimate relationship with the victim, victims tend to be women, and a firearm is most likely to be used. This study uses a newspaper surveillance methodology to examine such cases. Articles from the New York Times as found in the New York Times Index were coded, analyzed, and examined. The cases, 166 in total, support the findings from prior research. The trend data was examined by cross tabulations and chi‐square analysis. The findings suggest that murder–suicides are rare events and when they occur they usually involve a male perpetrator and an intimate partner victim who is either a wife or girlfriend with the event occurring in a private home. A firearm is the most commonly used method for both murders and suicides, particularly if there was more than one murder victim. The authors conclude by suggesting that future research should focus on using the forthcoming data resource in the CDC’s National Violent Death Reporting System (NVDRS) to examine the occurrence of murder–suicide.     

Characteristics and Prediction of Cranial Crush Injuries in Children*†

Abstract: This study documents four clinical cases of fatal crush injuries to children between 1.5 and 6 years of age with correlations between modeled stress and clinically observed fracture patterns. The clinical case fractures were concentrated in the basicranium, bridged the impact sites, and traversed the middle cranial fossa in the area of the spheno‐occipital synchondrosis. The crushing forces from these cases were recreated on a simplified finite element model of a cranium by applying bilateral pressures to corresponding regions. Numerous trials were run to develop a representative pattern of principal stress directions. In all cases, the highest tensile stresses were located on the basicranium and corresponded to the observed fracture path(s). These results suggest that prefailure stress field diagrams may predict fracture propagation paths, although these will not be exact. Also, these analyses indicate that quasi‐static bilateral loading of the cranium may lead to predictable fracture of the basicranium.     

Advanced Framework for Digital Forensic Technologies and Procedures*

Abstract: Recent trends in global networks are leading toward service‐oriented architectures and sensor networks. On one hand of the spectrum, this means deployment of services from numerous providers to form new service composites, and on the other hand this means emergence of Internet of things. Both these kinds belong to a plethora of realms and can be deployed in many ways, which will pose serious problems in cases of abuse. Consequently, both trends increase the need for new approaches to digital forensics that would furnish admissible evidence for litigation. Because technology alone is clearly not sufficient, it has to be adequately supported by appropriate investigative procedures, which have yet become a subject of an international consensus. This paper therefore provides appropriate a holistic framework to foster an internationally agreed upon approach in digital forensics along with necessary improvements. It is based on a top‐down approach, starting with legal, continuing with organizational, and ending with technical issues. More precisely, the paper presents a new architectural technological solution that addresses the core forensic principles at its roots. It deploys so‐called leveled message authentication codes and digital signatures to provide data integrity in a way that significantly eases forensic investigations into attacked systems in their operational state. Further, using a top‐down approach a conceptual framework for forensics readiness is given, which provides levels of abstraction and procedural guides embellished with a process model that allow investigators perform routine investigations, without becoming overwhelmed by low‐level details. As low‐level details should not be left out, the framework is further evaluated to include these details to allow organizations to configure their systems for proactive collection and preservation of potential digital evidence in a structured manner. The main reason behind this approach is to stimulate efforts on an internationally agreed “template legislation,” similarly to model law in the area of electronic commerce, which would enable harmonized national implementations in the area of digital forensics.