Multi-technique comparison of source and primary transfer soil samples: an experimental investigation.

The comparison of soil samples is of long-standing and increasing interest in forensic science. Routine comparisons should involve the use of several techniques in combination. A wide range of analytical techniques can be used, choice being dependent on several factors including sample size and character, time constraints and cost limitations. In this paper results are presented for experiments carried out to test the effectiveness of four of the available analytical techniques (spectro-photometric colour determination, laser diffraction particle size analysis, stable isotope analysis and chemical element analysis) used to compare single source and primary transfer soil samples. Four soil types and five footwear types were used. All four techniques showed excellent precision and good resolving power between soil types. Only relatively small differences were obtained between source and transferred soil samples in terms of colour, stable carbon and nitrogen isotope ratios and elemental chemistry. Slight but significant differences were found in grain size, indicating that the primary transfer process is to some extent grain size selective.     

Use of an acrylonitrile-butadiene-styrene (ABS) plastic ring as a matrix in the recovery of bite mark evidence

Valuable forensic information can be obtained from analysis of human bite mark injuries after careful retrieval of such evidence from living or deceased victims. It is difficult, however, to maintain the anatomical configuration of the skin, especially where body contours complicate the recovery process. Transillumination of the injury pattern in the skin after removal and preservation of the tissue from a deceased victim can provide significant information in the investigation process. A dimensionally stable matrix is required to support the skin's anatomical configuration during and after its removal. The authors have developed a unique and convenient method of heating and contouring a ring of acrylonitrile-butadiene-styrene (ABS) plastic using table salt over a heat source. When this ring is applied to the deceased victim's skin, and a backing material is added for support, removal of the skin and the bite mark can be accomplished more predictably while maintaining the anatomical contour. It is important to record bite marks accurately as soon after discovery as possible; the authors believe that this technique will significantly aid recovery of such evidence either at the crime scene or in the laboratory. A method of inscribing appropriate anatomical markers and case numbers on the rings is also described.     

Fly larvae: a new toxicological method of investigation in forensic medicine

Toxicological analyses on a putrefied cadaver are sometimes difficult to achieve because of the absence of blood and urine. In this study, maggots, living material, are proposed as a new medium of investigation in forensic medicine. Five drugs (triazolam, oxazepam, phenobarbital, alimemazine, and clomipramine) were identified and assayed in some tissues of a putrefied cadaver and in the maggots found on and in the body.     

The effect of tape type,taping method and tape storage temperature on the retrieval rate of fibres from various surfaces: An example of data generation and analysis to facilitate trace evidence recovery validation and optimisation

This paper aspires to assist those tasked with data generation and analysis for the purpose of the validation and/or optimisation of trace evidence recovery. It does so via a detailed report of the authors’ approach to this problem in the context of target fibre retrieval using self-adhesive tapes.Textile fibres can provide valuable evidence at both source and activity levels. This ability stems from their near ubiquity in the man-made environment, their potential for high levels of discrimination (especially when found in combination) and their reproducible transfer and persistence behaviours. To realise this value for the criminal justice system, it is vital that police forces and forensic providers are collectively able to search for, recover and analyse fibres found at crime scenes and correctly evaluate their evidential value.ISO accreditation provides quality assurance for such activities. The work reported in this paper was part of a study to validate crime scene fibre retrieval processes for the purposes of ISO17020 accreditation. However, it is hoped that it will be of assistance to those wishing to validate and/or optimise forensic fibre recovery whether at the crime scene or in the laboratory. Further, the methods described may be of value to those who need to validate and/or optimise the recovery of other types of trace evidence.This paper outlines a series of experiments that investigated the effect of four factors on the rate at which target fibres could be recovered from surfaces by tape lifting. The factors were tape type (with two levels, namely: J-LAR and Crystal Tabs), tape storage temperature (three levels: −5 °C, room temperature [19 ± 1 °C] and 35 °C), taping method (two levels: zonal and one-to-one) and surface (12 levels: each being a surface type commonly encountered at crime scenes). This resulted in 144 unique experimental conditions. For each of these, five repeat fibre recovery rate determinations were carried out, generating 720 data points. All surfaces were clean and dry prior to target fibres being transferred and recovered. In all cases, the tapes were applied to the surfaces at 19 ± 1 °C.These experiments showed that the surfaces can be divided into three stable clusters based on the median and interquartile range of the fibre retrieval rate achieved from each of them. Also, they showed that, in terms of the proportion of the target fibres retrieved, typically and setting aside interaction effects:

• •Crystal Tabs outperformed J-LAR;
• •rolls of tape stored at −5 °C and 35 °C outperformed those stored at room temperature;
• •one-to-one taping outperformed zonal taping.

However, notably, a good degree of between-condition overlap was also apparent in the data. To understand this, a four-way factorial ANOVA model was built which revealed significant and substantive effects for all four main effects and for 10 of the 11 interactions. Importantly, the four-way interaction term was amongst those found to be significant. The interplay between the effects of the four factors was analysed by means of simple effects tests and pairwise contrasts. Tables and interactive parallel coordinate plots have been created. Using these it can easily be seen which of any given pair of levels of each of the four factors resulted in the higher fibre retrieval rate under any one of the unique conditions of the study, and the effect size and statistical significance of this observation.Qualitative evaluations of the effect of tape storage temperatures on tape pliability and its propensity to tear in use were also made.     

Discrimination between sediment and soil samples for forensic purposes using elemental data: an investigation of particle size effects

This paper reports the results of an investigation to quantify variations in elemental concentrations amongst different particle size fractions obtained from a suite of sediment samples collected from the River Avon, UK. Concentrations of 49 elements determined by inductively coupled plasma spectrometry (ICP-AES and ICP-MS) were compared using conventional and multivariate statistical methods in order to assess compositional differences between different size fractions and between different samples. The results showed significant differences between different size fractions and the bulk sediments, but indicated that all of the size fractions considered (<150, 63-150, 20-63 and <20microm) provided an adequate basis on which to identify associations and differences between samples. It was concluded that, while in certain specific circumstances it may be most appropriate to make forensic comparisons based on a very narrowly defined particle size range, for the majority of purposes the <150microm fraction provides the best compromise between sample size requirements and data resolution.     

Forensic analysis of soil and sediment traces by scanning electron microscopy and energy-dispersive X-ray analysis: an experimental investigation

This paper reports the results of a series of experiments carried out to determine the precision of soil trace comparisons based on elemental peak height ratios determined by energy-dispersive X-ray analysis (EDXRA) in a variable pressure scanning electron microscope (VP-SEM). Experiments were conducted on 'bulk' soil aggregates, ground powders prepared from the <150 microm soil fractions and on smears of both the bulk soil and <150 microm material placed on cotton cloth. X-ray count data were obtained using area scans and spot analyses at different magnifications. The effects on elemental peak height ratios of varying the SEM chamber pressure, beam spot size, emission current and accelerating voltage were also examined. The peak height ratios for oxygen, silicon, aluminium, potassium, calcium and iron were found to show little variation as a function of chamber pressure, spot size and emission current over the ranges examined, but a strong dependency on accelerating voltage was observed. Within-sample variation in results, expressed by the percentage coefficient of variation, was found to be lowest for area scan analyses of the ground <150 microm fractions and greatest for the spot analyses of the bulk soil aggregates and the <150 microm fractions. We conclude that comparison of elemental peak height ratios determined by EDXRA can be a useful tool for rapid screening of soil samples, especially when combined with investigation of other attributes of the soil traces such as colour, fabric and the composition, shapes and surface textures of individual particles or aggregates within the soil traces. If sufficient material is available and can be readily separated without contamination or loss, higher resolution and more precise elemental data should be obtained by methods such as inductively coupled plasma atomic-emission spectrometry (ICP-AES) or mass-spectrometry (ICP-MS).     

A high-throughput urinalysis of abused drugs based on a SPE-LC-MS/MS method coupled with an in-house developed post-analysis data treatment system

A rapid urinalysis system based on SPE-LC-MS/MS with an in-house post-analysis data management system has been developed for the simultaneous identification and semi-quantitation of opiates (morphine, codeine), methadone, amphetamines (amphetamine, methylamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA) and 3,4-methylenedioxymethamphetamine (MDMA)), 11-benzodiazepines or their metabolites and ketamine. The urine samples are subjected to automated solid phase extraction prior to analysis by LC-MS (Finnigan Surveyor LC connected to a Finnigan LCQ Advantage) fitted with an Alltech Rocket Platinum EPS C-18 column. With a single point calibration at the cut-off concentration for each analyte, simultaneous identification and semi-quantitation for the above mentioned drugs can be achieved in a 10 min run per urine sample. A computer macro-program package was developed to automatically retrieve appropriate data from the analytical data files, compare results with preset values (such as cut-off concentrations, MS matching scores) of each drug being analyzed and generate user-defined Excel reports to indicate all positive and negative results in batch-wise manner for ease of checking. The final analytical results are automatically copied into an Access database for report generation purposes. Through the use of automation in sample preparation, simultaneous identification and semi-quantitation by LC-MS/MS and a tailored made post-analysis data management system, this new urinalysis system significantly improves the quality of results, reduces the post-data treatment time, error due to data transfer and is suitable for high-throughput laboratory in batch-wise operation.     

Screening of soil evidence by a combination of simple techniques: validity of particle size distribution.

The validity of the determination of particle size distribution for forensic soil identification was studied using 73 soil samples collected from a 20 km x 15 km area. Soil particles were first divided into two fractions by wet sieving with a sieve with a 0.05 mm aperture size. Dry sieving was used to analyze the coarse particle fraction and a particle size analyzer was used for the fine particle fraction. The number of particle size classes measured by sieving could be reduced to three, <0.05, 0.05-0.2, and 0.2-2 mm, which enabled 87.9% of the soil samples to be discriminated. Measurements made with the particle size analyzer on the fine particle fraction increased the discriminating power to 95.9%. The use of particle size analysis by sieving in combination with color examination allowed us to discriminate 99.5% of the soil samples, even when particle size analysis of the fine particle fraction was not carried out.     

The evaluation of evidence in the forensic investigation of fire incidents (Part I): an approach using Bayesian networks

The forensic investigation of the origin and cause of a fire incident is a particularly demanding area of expertise. As the available evidence is often incomplete or vague, uncertainty is a key element. The present study is an attempt to approach this through the use of Bayesian networks, which have been found useful in assisting human reasoning in a variety of disciplines in which uncertainty plays a central role. The present paper describes the construction of a Bayesian network (BN) and its use for drawing inferences about propositions of interest, based upon a single, possibly non replicable item of evidence: detected residual quantities of a flammable liquid in fire debris.     

Experimental validation of forensic evidence: a study of the decomposition of buried pigs in a heavy clay soil.

In a murder investigation, where the victim had been strangled and buried in a shallow grave, there were discrepancies between the post mortem interval (PMI) as estimated from entomological studies and estimations determined from other evidence. This inconsistency provided the impetus for examining the decay process using pig carcasses as analogues for the human cadaver. The pigs were buried in the immediate vicinity of the original burial site in December 1996, which was the month when the victim was purported to have been interred in the previous year. The buried pigs were then monitored for 5 months which, based on the evidence other than the entomological, was the period over which the corpse was thought to have lain in the ground. The pig corpses were disturbed by scavengers in mid April: this was the same time that the human corpse was discovered in the previous year by scavengers. Insects played no role in the decomposition process until the pig carcasses had been exposed by animals. Blowflies, notably Calliphora vomitoria, were attracted to the exposed tissues and laid eggs from which larvae developed. Calliphora vomitoria is a species often used to estimate PMI. This investigation has shown that soil conditions and low seasonal temperatures had preserved the pig carcasses for longer than might be expected. Using the blowfly larvae to estimate PMI would have produced erroneous results had not the burial environment and exhumation history been investigated.     

Strontium-90 as an indicator of time since death: a pilot investigation.

The results of a pilot investigation are presented. The study aimed to show that the presence of radioactive strontium-90 in human bone could be used as evidence of active uptake during life. In this way the time since death of the individual could be identified as occurring before or after the date when atmospheric levels of radioactive strontium were at a peak in the early 1960s. The results of this initial investigation were encouraging but further detailed analysis is required on a substantially larger sample of material spanning a more controlled time period.     

A method for calculating the strength of evidence associated with an earwitness's claimed recognition of a familiar speaker

The present paper proposes and demonstrates a method for assessing strength of evidence when an earwitness claims to recognize the voice of a speaker who is familiar to them. The method calculates a Bayes factor that answers the question: What is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was the suspect versus what is the probability that the earwitness would claim to recognize the offender as the suspect if the offender was not the suspect but some other speaker from the relevant population? By “claim” we mean a claim made by a cooperative earwitness not a claim made by an earwitness who is intentionally deceptive. Relevant data are derived from naïve listeners' responses to recordings of familiar speakers presented in a speaker lineup. The method is demonstrated under recording conditions that broadly reflect those of a real case.     

Fatal fall of an aircraft stowaway: a demonstration of the importance of death scene investigation

Scene investigation is of paramount importance in forensic pathology. Many medical and coroner systems wisely and routinely evaluate the scene in homicides but do not routinely investigate traffic fatality scenes. This case originally was thought to be a pedestrian-automobile event, but, due to proper and prompt scene investigation, it was determined that the decedent was actually a wheel-well stowaway who fell from a commercial aircraft.     

Multi-technique comparison of source and primary transfer soil samples: an experimental investigation by D Croft and K Pye. A comment.

The Croft and Pye paper has a story to tell about the differentiation capabilities of four analytical techniques. It is not however, the whole story. This may be due in part to the lack of reproducibility in the generation of results, and also in the effort to match soil samples and thus infer that the results provide stronger conclusions than is possible to make with this sort of analysis. More research must be done to establish in what instances these techniques and others provide reliable, reproducible, representative and accurate results, and in what capacity such results can be presented. As they stand, the results from this paper should be treated with great caution and not extrapolated to any other forensic case work until greater reliability of these and other techniques has been established.     

The role of coronial autopsies in a context of decreasing hospital autopsies: an investigation of the issues

This article scrutinises the argument that decreasing hospital autopsy rates are outside the control of medical personnel, based as they are on families' unwillingness to consent to autopsy procedures, and that, as a consequence, the coronial autopsy is the appropriate alternative to the important medical and educational role of the autopsy It makes three points which are well supported by the research. First, that while hospital autopsy rates are decreasing, they have been doing so for more than 60 years, and issues beyond the simple notion of consent, like funding formulae in hospitals, increased technology and fear of litigation by doctors are all playing their part in this decline. Secondly, the issue of consent has as much to do with families not being approached as with families declining to give consent. This is well supported by recent changes in hospital policy and procedures which include senior medical personnel and detailed consent forms, both of which have been linked to rising consent rates in recent years. Finally, the perception that coronial autopsies are beyond familial consent has been challenged recently by legislative changes in both Australia and the United States of America which allow objections based on religion and culture to be heard by coroners. For these reasons, it is argued that medical personnel need to focus on increasing hospital autopsy rates, while also addressing the complex ethical issues associated with conducting medical research within the context of the coronial autopsy.     

Determination of barbiturates in hair samples by using a validated UHPLC-HRMS method: application in investigation of drug-facilitated sexual assault

In recent years,benzodiazepines and benzodiazepine-like drugs are the most common substances associated with drug-facilitated sexual assaults(DFSA);however,barbiturates are also detected occasionally.Segmental hair analysis provides useful information on the historic pattern of drug use,enabling differentiation between single exposure in DFSA cases and chronic use.However,sensitive and specific methods for barbiturate analysis in hair samples are needed.Herein,we present an ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry(UHPLC-HRMS)method for qualitative and quantitative determination of seven barbiturates in hair samples.Firstly,a hair strand was decontaminated and then freeze-milled in liquid nitrogen.Next,50mg of powdered hair was extracted with methanol in an ultrasonic bath for 10 min in the presence of 10 ng phenobarbital-d5.The supernatant was dried under nitrogen gas,and the pellet was dissolved in 100 μL mobile phase.Afterwards,10 μL of the suspension was injected into the UHPLC-HRMS system.The present method involved two UHPLC conditions for determination of barbiturates(I)and identification of the structural isomers amobarbital and pentobarbital(II).This method showed satisfactory linearity in a range of 0.02–20.00 ng/mg for UHPLC conditions I and II,both with a high determination coefficient(0.9991–0.9999).The selectivity,intra-and interday precision,accuracy and matrix effect of the method were acceptable.Next,the validated method was applied to investigate an authentic DFSA case.Hair samples(black,approximate 25cm long)were collected 3 months after the assault,and the proximal segments(0–5 cm from the root;each segment was 1 cm long)were analysed.Amobarbital was detected at a concentration of相似文献   

Domestic violence during pregnancy in an eastern city of Turkey: a field study

Violence is an increasing and important community health problem that can be seen in any area of human life. Limited studies were found about domestic violence among pregnant women and its relation with social status of women. The aim of this study was to determine the prevalence and types of domestic violence during pregnancy, factors affecting it, women's thoughts about violence, and relation between social status of women and domestic violence. This cross-sectional study was conducted on 253 pregnant women, using cluster and simple random sampling methods. Chi-square test and logistic regression analysis methods were used to analyze the data. Women who indicated that they have been exposed to violence at some point of their lives were 24.1% and who indicated that violence continued while they were pregnant were 11.1%. Physical violence was the most common type of violence reported (18.2%). It was found that women who had primary school or lower level of education and who made unwanted marriage suffered from more violence during pregnancy. It can be said that violence against pregnant women is still a social problem. In societies where gender roles are dominant, decision makers have to take necessary steps such as supporting education of girls to improve social status of women, increasing awareness among women in regard to personal rights and legal regulations which will contribute to the solution of the issue.     

Latent evidence detection using a combination of near infrared and high dynamic range photography: an example using bloodstains

In this paper, we use bloodstains to illustrate an approach for identifying latent evidence on dark cloth using near infrared (NIR) photography combined with high dynamic range (HDR) photography techniques. NIR photography alone has been used to capture latent evidence that cannot be seen in normal ambient light. HDR techniques combine multiple bracketed photographs of the same image to increase the dynamic range of the photograph which can provide greater contrast. Using NIR photography alone, we were able to detect a bloodstain up to a 1/16 dilution, an improvement over previous studies. Combining NIR photography with the HDR process resulted in a noticeable increase in visibility up to 1/16 dilution when compared to NIR photographs alone. At 1/32 dilution, we were able to detect bloodstains that were not visible using NIR alone. NIR is a useful tool for imaging latent evidence, and combining NIR with HDR consistently provides better results over NIR alone.