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PubMed1992

Determination of methamphetamine enantiomer ratios in urine by gas chromatography-mass spectrometry.

Analysis of the enantiomers of methamphetamine and its metabolite amphetamine is an extremely important process for a number of scientific disciplines. From studies of biological activity and mechanisms through determination of precursor molecules in a criminal investigation are all served by this analytical procedure. Utilization of gas chromatography-mass spectrometry with chiral derivatizing reagents is the most common chiral procedure and produces excellent results. Of the chiral derivatizing reagents available, the most widely used is trifluoroacetyl-l-prolyl chloride (TPC). Utilization of other derivatives require either synthesis by the analyst or have not shown themselves to provide as good a separation as did the TPC reagent. Use of chiral stationary phases yield good results but the disadvantages of temperature limits of these columns and the narrow use to which the columns can be put has limited their utilization. A significant utility of the chiral stationary phase is the ability to determine the purity of a chiral derivatizing reagent. Even if not used for routine analysis of enantiomers, utilization of this procedure can determine the purity of a reagent such as TPC and allow for accurate calculation of actual amounts of each enantiomer. This can be estimated using chiral derivatives on an achiral column, but it is limited to the extent that it is not able to differentiate enantiomeric impurity in the reagent versus the drug itself. Description of chromatographic procedures primarily focusing on gas chromatographic-mass spectrometric techniques but also including liquid chromatographic techniques along with examples of extraction and derivatization procedures is the focus of this review.

Gas Chromatography-Mass Spectrometry↗

PubMed1993

DNA-profiling of stains in criminal cases: analysis of measurement errors and band-shift. Discussion of match criteria.

DNA-profiling was performed on approximately 600 stains (blood, semen/vaginal secretion, tissue samples and saliva) deriving from criminal investigations. The restriction enzyme was HinfI, and the VNTR (variable number of tandem repeats) probes were MS1, MS31, MS43a and YNH24. DNA-profiles were obtained from 60% of the stains, and matches were seen for 65% of the profiles. The measurement errors and the differences between corresponding fragment lengths of blood and stain profiles were analysed statistically. Distinct band-shifts were observed for approximately 65% of the profiles. For 50% of the profiles, the fragments derived from the stain fragments migrated faster than those from the blood sample, and for 15% of the profiles the stain fragments migrated slower. The difference between the migration distance of the stain and the blood fragments of a given pair of profiles increased with increasing migration distance, i.e. with decreasing fragment length. After correction for this slope the measurement errors were independent of the fragment length, and of the same order of size as for duplicate determinations of fragments from blood samples. The differences between the fragment lengths of corresponding profiles were highly correlated (rho = 0.8). Based on the statistical analysis, different match criteria are discussed and an ellipsoid accept-area is suggested.

Blood Stains↗

PubMed2005

Inference of human geographic origins using Alu insertion polymorphisms.

The inference of an individual's geographic ancestry or origin can be critical in narrowing the field of potential suspects in a criminal investigation. Most current technologies rely on single nucleotide polymorphism (SNP) genotypes to accomplish this task. However, SNPs can introduce homoplasy into an analysis since they can be identical-by-state. We introduce the use of insertion polymorphisms based on short interspersed elements (SINEs) as a potential alternative to SNPs. SINE polymorphisms are identical-by-descent, essentially homoplasy-free, and inexpensive to genotype using a variety of approaches. Herein, we present results of a blind study using 100 Alu insertion polymorphisms to infer the geographic ancestry of 18 unknown individuals from a variety of geographic locations. Using a Structure analysis of the Alu insertion polymorphism-based genotypes, we were able to correctly infer the geographic affiliation of all 18 unknown human individuals with high levels of confidence. This technique to infer the geographic affiliation of unknown human DNA samples will be a useful tool in forensic genomics.

Alu Elements↗

PubMed2006

Forensic veterinary radiology: ballistic-radiological 3D computertomographic reconstruction of an illegal lynx shooting in Switzerland.

The lynx, which was reintroduced to Switzerland after being exterminated at the beginning of the 20th century, is protected by Swiss law. However, poaching occurs from time to time, which makes criminal investigations necessary. In the presented case, an illegally shot lynx was examined by conventional plane radiography and three-dimensional multislice computertomography (3D MSCT), of which the latter yielded superior results with respect to documentation and reconstruction of the inflicted gunshot wounds. We believe that 3D MSCT, already described in human forensic-pathological cases, is also a suitable and promising new technique for veterinary pathology.

Animals↗

PubMed2005

Regulation of ABO gene expression.

The ABO blood group system is important in blood transfusions and in identifying individuals during criminal investigations. Two carbohydrate antigens, the A and B antigens, and their antibodies constitute this system. Although biochemical and molecular genetic studies have demonstrated the molecular basis of the histo-blood group ABO system, some aspects remain to be elucidated. To explain the molecular basis of how the ABO genes are controlled in cell type-specific expression, during normal cell differentiation, and in cancer cells with invasive and metastatic potential that lack A/B antigens, it is essential to understand the regulatory mechanism of ABO gene transcription. We review the transcriptional regulation of the ABO gene, including positive and negative elements in the upstream region of the gene, and draw some inferences that help to explain the phenomena described above.

ABO Blood-Group System↗

PubMed2026

Quantitative assessment of the fingerprint evidential value using machine learning.

Fingerprints as physical evidence have long supported criminal investigation and adjudication. In practice, however, fingerprint identification relies mainly on examiners' experience. Furthermore, expert opinions tend to be categorical, even though the opinions with the same conclusion could differ substantially in evidential strength. To quantitatively assess fingerprint evidential value, this study proposes a machine learning-based framework as an interpretable decision-support tool. A lightweight residual one-dimensional convolutional neural network was constructed, incorporating channel recalibration and a similarity-driven attention mechanism to learn adaptive contribution weights for different matched minutiae (minutiae for short). Controlled experiments revealed that the predicted evidential value increased with the number of minutiae and was significantly influenced by the quality of minutiae. With 10 minutiae, the mean predicted scores were 4.49, 7.00, and 9.09 for blurred, moderately blurred, and clear minutiae, respectively. Multiple regression analysis indicated that replacing a pair of blurred minutiae with a pair of clear minutiae increased the score by 0.492, whereas replacing it with a pair of moderately blurred minutiae increased the score by only 0.216. By mapping predicted scores to graded levels of evidential strength, the framework contributes to a paradigm shift from categorical expert opinions to graded ones, helping courts evaluate fingerprint evidence more scientifically.

Humans↗

PubMedDate not supplied

Identifying the residential location of rapists.

The spatial offence behaviour of 45 British serial rapists was examined in order to generate a predictive model, of use to criminal investigators. Two alternative hypotheses were explored. One predicted that rapists would commute into an area to carry out their offence. The second predicted that they would "maraud" out from a fixed location. Of the 45 offenders, 39 fitted the "maurader" hypothesis. However, the area covered by this model was an average of nearly 180 square miles. A second complementary theory, developed from facets of offenders' backgrounds, was therefore used to refine the predictions of distance travelled to and between offences. This enabled the size of the residential zone predicted from the marauder model to be reduced to a mean area of just over ten square miles. Tests of these models, combined into a small scale expert system, predicted the correct area for 82% of the cases. Suggestions for the further development of this expert system are discussed.

Adolescent↗

PubMedDate not supplied

An analysis of allegations of sexual abuse in a multi-victim day-care center case.

Sexual abuse in day-care centers is a phenomenon of increasing concern, both in terms of its prevalence and its serious effects on child victims. Legal intervention in this area is problematic because criminal investigations are usually beset with difficulties: Characteristics of children and of the abuse situation affect disclosure rates and credibility. Research on children as witnesses is amassing; however, so far, little systematic analysis has been conducted on multi-victim child sexual abuse cases. The present study concerns a case of sexual abuse in a day-care center with over 100 alleged victims. Criteria derived from Statement Validity Analysis (SVA) protocols were applied to aggregate record review data to assess the veritability of the abuse allegations. Individual children's abuse disclosures were also analyzed, vis-à-vis characteristics of the children (age, gender, recency of attendance) and of the investigation (agency doing the interview, number of interviews, use of anatomically detailed dolls). The use of SVA criteria supported the veritability of allegations in this day-care abuse case. Even acknowledging the limitations of archival data collected for other purposes, the aggregate data analysis reflected consistency, logical structure, and spontaneity; however, little evidence of accommodation was found. Multivariate comparison of disclosing and nondisclosing children found an unexpected inverse relationship of disclosure with age, as well as positive associations with number of interviews and use of dolls. Alternative interpretations of these results are discussed.

Age Factors↗

PubMed2001

Diagnosis of cyanide intoxication by measurement of cytochrome c oxidase activity.

Cytochrome c oxidase (CCO), a mitochondrial enzyme, is inactivated by cyanide or carbon monoxide (CO) intoxication. We measured CCO activity, in the major organs of the rat at various times after death caused by cyanide intoxication. Tissue samples were homogenized, and the CCO activity in the mitochondrial fraction was measured using ferrous cytochrome c as the substrate. The CCO activity inhibition was highest in the brain, although the cyanide concentration was lowest level. As a result of this and the clinical symptoms displayed, we consider the brain to be the primary organ of cyanide intoxication. As cyanide is highly toxic to humans, in small amounts and many patients and victims have already had some medical care, it is difficult to detect cyanide in criminal investigations. The CCO activities in various organs remained significantly low for 2 days after the cyanide intoxication, suggesting that the diagnosis may be possible by measuring not only the cyanide concentration but also the CCO activity.

Animals↗

PubMed2002

Hair-MAP: a prototype automated system for forensic hair comparison and analysis.

This paper demonstrates the feasibility of the automation of forensic hair analysis and comparison task using neural network explanation systems (NNESs). Our system takes as input microscopic images of two hairs and produces a classification decision as to whether or not the hairs came from the same person. Hair images were captured using a NEXTDimension video board in a NEXTDimension color turbo computer, connected to a video camera. Image processing was done on an SGI indigo workstation. Each image is segmented into a number of pieces appropriate for classification of different features. A variety of image processing techniques are used to enhance this information. Use of wavelet analysis and the Haralick texture algorithm to pre-process data has allowed us to compress large amounts of data into smaller, yet representative data. Neural networks are then used for feature classification. Finally, statistical tests determine the degree of match between the resulting collection of hair feature vectors. An important issue in automation of any task in criminal investigations is the reliability and understandability of the resulting system. To address this concern, we have developed methods to facilitate explanation of neural network's behavior using a decision tree. The system was able to achieve a performance of 83% hair match accuracy, using 5 of the 21 morphological characteristics used by experts. This shows promise for the usefulness of a fuller scale system. While an automated system would not replace the expert, it would make the task easier by providing a means for pre-processing the large amount of data with which the expert must contend.

Algorithms↗

PubMed2003

Methamphetamine impurity profiling using a 0.32 mm i.d. nonpolar capillary column.

Classification of seized methamphetamine by impurity profiling can provide very useful information in criminal investigations of drug traffic routes, sources of supply and relationships between seizures. The aim of this study is to improve and develop an analytical method for detecting impurities such as starting materials and by-products in illegally prepared methamphetamine.HCl samples. A 50mg sample of methamphetamine.HCl was dissolved in 1 ml of buffer solution (four parts 0.1M phosphate buffer pH 7.0 and one part 10% Na2CO3). Impurities were extracted with 0.5 ml of ethyl acetate containing four internal standards (ISs) (n-decane, n-pentadecane, n-nonadecane and n-hexacosane) and analyzed by gas chromatography (GC) using a flame ionization detector (FID) on a DB-5 capillary column (0.32 mmi.d. x 30 m, film thickness 1.0 microm). The use of a middle-bore column offered better separation of the impurity peaks. The correction of the retention times of impurity peaks with four ISs made peak identification very accurate for subsequent data processing. Twenty-four characteristic peaks were selected for comparison and similarity and/or dissimilarity between samples, and the data were evaluated by the Euclidean distance of the relative peak areas after logarithmic transformation. The results indicate that the present method would be useful for methamphetamine impurity profiling.

Chromatography, Gas↗

PubMed2003

Statistical analysis of impact parameters of soft nose bullet fired on windowpane.

Proper collection of glass evidence from crime spot is very important for its latter probative values. Glass evidence when properly collected and analyzed becomes a powerful witness and it can speak truth long after the crime. In criminal investigation glass evidence can tell what had happened and when it had happened. In the present study, a statistical regression analysis relationship between thickness of windowpane used as targets by soft nose bullet using.315"/8mm caliber sporting gun made in ordnance factory, India and various associated impact parameters were investigated. The relationship is found to be reasonably linear. The ballistics performance of windowpane has been found to correlate with the shear strength behavior above the elastic limit.

Journal Article↗

PubMed1999

Importance of storing emergency serum samples for uncovering murder with insulin.

A case of a previously healthy 48-year-old man murdered by exogenous insulin administration is reported. The patient was delivered unconscious to the emergency unit. Initially, treatment with hyperbaric oxygen was commenced because decompression sickness was suspected. However, the treatment was aborted as the patient was found to be hypoglycaemic (nadir serum glucose 0.3 mmol/l) and treatment and diagnostics of hypoglycaemia commenced. Brain damage due to hypoglycaemia was severe, and the patient remained in a vegetative state for 2 months before he died of multiorgan failure. Serum samples drawn at admittance were stored frozen, whereby it was possible to show retrospectively, that while the concentration of insulin in serum was high (75 mU/l, increasing further to over 240 mU/l in the next few hours) concentration of C-peptide was low (below detection limit of 0.1 nmol/l) at the hypoglycaemic stage. It was concluded that the patient had received exogenous insulin somehow, and the police was informed. Circumstantial evidence obtained during ensuing criminal investigation was considered by the court to prove the patient's wife (a nurse) guilty of murder. The availability of stored frozen serum samples drawn at the early stage of hospitalization helped to uncover the crime involved in our case.

Blood Glucose↗

PubMed2001

Identification of reddish alcoholic beverages by GC/MS using aroma components as indicators.

A method to identify reddish alcoholic beverages used for dissolving stimulant drugs was devised using aroma components as indicators. Thirteen brands of beverages including red wines, blueberry liquors, raspberry liquors, strawberry liquor, a mixture of red wine and blueberry juice and a mixture of red wine and grape juice were examined. Aroma components in each sample were effectively concentrated with a porous polymer beads column (Porapak Q) and were analyzed by gas chromatography/mass spectrometry (GC/MS). Specific aroma components were detected in each beverage and reddish alcoholic beverages were successfully classified into five groups using five aroma components as indicators. The present method should prove to be useful in criminal investigations.

Journal Article↗

PubMed2003

Bone finds: a challenge to forensic science.

The study presented here is based on 176 forensic dental reports compiled between 1993 and 2001. The bulk of the research took place in 1997, when major construction at Potsdamer Platz and Lehrter Bahnhof in central Berlin required the excavation of considerable quantities of earth. As building proceeded here, at 'Europe's biggest construction site', it revealed not only a large number of long bones, but also a great many skulls and skull fragments. In five instances, complete skeletons were unearthed. Many of the bones ultimately proved to be of animal origin. The police were not instructed to open a single criminal investigation. Identifying and piecing together the material in this context makes tremendous demands of forensic osteology. Establishing the nature of these finds beyond reasonable doubt, and putting a name and date to them, calls for interdisciplinary co-operation between experts in odontology, anthropology, anatomy, radiology and veterinary medicine, not to mention historians.

Berlin↗

PubMedDate not supplied

The collation of forensic DNA case data into a multi-dimensional intelligence database.

The primary aim of any DNA Database is to link individuals to unsolved offenses and unsolved offenses to each other via DNA profiling. This aim has been successfully realised during the operation of the New Zealand (NZ) DNA Databank over the past five years. The DNA Intelligence Project (DIP), a collaborative project involving NZ forensic and law enforcement agencies, interrogated the forensic case data held on the NZ DNA databank and collated it into a functional intelligence database. This database has been used to identify significant trends which direct Police and forensic personnel towards the most appropriate use of DNA technology. Intelligence is being provided in areas such as the level of usage of DNA techniques in criminal investigation, the relative success of crime scene samples and the geographical distribution of crimes. The DIP has broadened the dimensions of the information offered through the NZ DNA Databank and has furthered the understanding and investigative capability of both Police and forensic scientists. The outcomes of this research fit soundly with the current policies of 'intelligence led policing', which are being adopted by Police jurisdictions locally and overseas.

Databases, Nucleic Acid↗

PubMedDate not supplied

Automatic forensic face recognition from digital images.

Digital image evidence is now widely available from criminal investigations and surveillance operations, often captured by security and surveillance CCTV. This has resulted in a growing demand from law enforcement agencies for automatic person-recognition based on image data. In forensic science, a fundamental requirement for such automatic face recognition is to evaluate the weight that can justifiably be attached to this recognition evidence in a scientific framework. This paper describes a pilot study carried out by the Forensic Science Service (UK) which explores the use of digital facial images in forensic investigation. For the purpose of the experiment a specific software package was chosen (Image Metrics Optasia). The paper does not describe the techniques used by the software to reach its decision of probabilistic matches to facial images, but accepts the output of the software as though it were a 'black box'. In this way, the paper lays a foundation for how face recognition systems can be compared in a forensic framework. The aim of the paper is to explore how reliably and under what conditions digital facial images can be presented in evidence.

Electronic Data Processing↗

PubMed2002

Disaster mental health services following the 1995 Oklahoma City bombing: modifying approaches to address terrorism.

How did the 1995 Oklahoma City bombing differ from prior disasters and what implications did it have for disaster mental health services and service delivery? The federal disaster mental health approach in this country developed largely out of experiences with natural disasters. The 1995 Oklahoma City bombing differed in several important ways, including the large number of human casualties, higher rates of psychopathology, and an extended period of concern due to the criminal investigation and trials, which suggested the need to consider modifications in the program. Outreach was extensive, but psychiatric morbidity of direct victims was greater than that of victims of natural disasters, emphasizing the need for attention to the triage and referral process. Other concerns that warrant consideration include practices related to record keeping and program evaluation.

Journal Article↗