On non-invasive 2D and 3D Chromatic White Light image sensors for age determination of latent fingerprints

The feasibility of 2D-intensity and 3D-topography images from a non-invasive Chromatic White Light (CWL) sensor for the age determination of latent fingerprints is investigated. The proposed method might provide the means to solve the so far unresolved issue of determining a fingerprints age in forensics. Conducting numerous experiments for an indoor crime scene using selected surfaces, different influences on the aging of fingerprints are investigated and the resulting aging variability is determined in terms of inter-person, intra-person, inter-finger and intra-finger variation. Main influence factors are shown to be the sweat composition, temperature, humidity, wind, UV-radiation, surface type, contamination of the finger with water-containing substances, resolution and measured area size, whereas contact time, contact pressure and smearing of the print seem to be of minor importance. Such influences lead to a certain experimental variability in inter-person and intra-person variation, which is higher than the inter-finger and intra-finger variation. Comparing the aging behavior of 17 different features using 1490 time series with a total of 41,520 fingerprint images, the great potential of the CWL technique in combination with the binary pixel feature from prior work is shown. Performing three different experiments for the classification of fingerprints into the two time classes [0, 5h] and [5, 24h], a maximum classification performance of 79.29% (kappa=0.46) is achieved for a general case, which is further improved for special cases. The statistical significance of the two best-performing features (both binary pixel versions based on 2D-intensity images) is manually shown and a feature fusion is performed, highlighting the strong dependency of the features on each other. It is concluded that such method might be combined with additional capturing devices, such as microscopes or spectroscopes, to a very promising age estimation scheme.     

Fingermark detection on non-porous and semi-porous surfaces using YVO4:Er,Yb luminescent upconverting particles

This article describes the use of an anti-Stokes luminescent material (upconverter), yttrium vanadate doped with ytterbium and erbium (YVO(4):Er,Yb), for the development of latent fingermarks on a range of non-porous surfaces. Anti-Stokes luminescent materials emit light at shorter wavelengths than the excitation wavelength. This property is unusual in both natural and artificial materials commonly found as exhibits in forensic science casework. As a result, fingermark detection techniques based on anti-Stokes luminescence are potentially extremely sensitive and selective. Latent fingermarks on non-luminescent and inherently luminescent substrates, including Australian polymer banknotes (a well-known 'difficult' surface), were developed with YVO(4):Er,Yb by dry powder and wet powder techniques. The effectiveness of YVO(4):Er,Yb for fingermark detection was compared with that of cyanoacrylate fuming and of sodium yttrium tetrafluoride doped with ytterbium and erbium (NaYF(4):Er,Yb). The results illustrate some benefit of luminescent up-converting phosphors over traditional luminescence techniques for the detection of latent fingermarks.     

Detection of polybrominated biphenyl ethers (PBDEs) in pediatric hair as a tool for determining in utero exposure

This study presents the prevalence of ethanol and illicit drugs in fatal road traffic accident victims in the Centre of Portugal between January 1990 and December 2007. Among the violent deaths, road traffic accidents presented the highest percentage (around 35%; n=3095), but decreasing throughout the years. Accidents were preponderant in males (about 80%; n=2402), between 21 and 30 years-old. Accidents involving drivers (55%; n=1310) were of the most common, being the car the main vehicle (45%), followed by the motorcycle (40%). An alcohol analysis request was present in 50% of the cases (n=1687), but increasing each year. Ethanol concentrations >1.2g/L, the legal limit in Portugal, were found in 55% (n=283) of the cases. Concerning drugs of abuse requests, only 4.4% (n=137) and 17.3% (58 cases) of the cases included the analysis at the Forensic Pathology Department (FPD) and at the Medico-Legal Office (MLO), respectively. Among the road accident cases analysed, 18 were positive, mainly in men (84%), between 21 and 30 years-old; opiates (47.1%; n=8) and cannabinoids (50%; n=4) were the most found, at the FPD and at the MLO, respectively. In conclusion, ethanol was identified as a key factor to traffic accidents, which explains the definition of specific legislation and methods of enforcement to prohibit this form of impairing. Nevertheless, ethanol still remains the psychoactive substance most frequently identified in the blood of divers killed in road-traffic crashes, recommending additional actions of supervision and control.     

Experimental study of the expansion dynamic of 9 mm Parabellum hollow point projectiles in ballistic gelatin

We study in this paper the expanding behaviour of hollow point 9 mm Parabellum projectiles (Hornady XTP(?) and Speer Gold Dot(?)). We defined a deformation rate that takes into account both the diameter increase and the length reduction. We plotted the behaviour of this parameter versus impact velocity (we refer to this curve as the expanding law). This expanding law has been plotted for different gelatin weight ratios and different gelatin block lengths. We completed our experiments with a set of high speed movies in order to correlate the deceleration to the state of expansion and size of the temporary cavity. Our results pointed out that full expansion is reached shortly after the projectile fully penetrates the gelatin. This result shows that the key point to accurately simulate human body interaction with a hollow point projectile is to accurately simulate the interface (skin, skull, clothes thoracic walls). Simulating accurately organs is only an issue if a quantitative comparison between penetration depths is required, but not if we only focus on the state of expansion of the projectile. By varying the gelatin parameters, we discovered that the expanding law exhibits a velocity threshold below which no expansion occurs, followed by a rather linear curve. The parameters of that expanding law (velocity threshold and line slope) vary with the gelatin parameters, but our quantitative results demonstrate that these parameters are not extremely critical. Finally, our experiments demonstrate that the knowledge of the expansion law can be a useful tool to investigate a gunshot in a human body with a semi-jacketed projectile, giving an estimation of the impact velocity and thus the shooting distance.     

Significantly increased detection rate of drugs of abuse in urine following the introduction of new German driving licence re-granting guidelines

In this paper we present the first assessment of the new German driving licence re-granting medical and psychological assessment (MPA) guidelines by comparing over 3500 urine samples tested under the old MPA cut-offs to over 5000 samples tested under the new MPA cut-offs. Since the enzyme multiplied immunoassay technique (EMIT) technology used previously was not sensitive enough to screen for drugs at such low concentrations, as suggested by the new MPA guidelines, enzyme-linked immunosorbent assay (ELISA) screening kits were used to screen for the drugs of abuse at the new MPA cut-offs. The above comparison revealed significantly increased detection rates of drug use or exposure during the rehabilitation period as follows: 1.61, 2.33, 3.33, and 7 times higher for 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), morphine, benzoylecgonine and amphetamine respectively. The present MPA guidelines seem to be more effective to detect non-abstinence from drugs of abuse and hence to detecting drivers who do not yet fulfil the MPA requirements to regain their revoked driving licence.     

Managing commingled remains from mass graves: considerations, implications and recommendations from a human rights case in Chile

This paper focuses on a little discussed part of Chilean history and the efforts to resolve Human Rights cases from the period 1973 to 1990. A case file is presented to illustrate the different stages, problems and solutions found in one particularly challenging case studied by the Special Unit of Identification of Detained and Missing (UEIDDDD) of the Human Rights Program of the Forensic Service, Chile, during the period 2006-2009. A major complication found in this example was the fact that the remains studied were commingled, and in addition, were mixed with remains that were not of medico-legal interest - deposited prior to and after the case in question, but within the same common grave. Multiple burials and the consequences of commingled skeletal human remains are reviewed, paying special attention to the roles that different agents related to these types of cases play, how they influence the decision making process and the outcomes that can be expected in commingled cases due to the complexities and challenges they present. Effective communication between prosecutors and forensic practitioners is vital to optimize the resources. Equally important is the relationship that is built between the practitioners and the victims' families regarding communication, information and expectations that both parties may have.     

Development of an immunoassay for the differentiation of menstrual blood from peripheral blood

This study examined all unintentional firearm fatalities while hunting that occurred in Sweden between 1983 through 2008. The circumstances as well as the impact of the hunter's exam on fatality frequency were analysed. During these 26 years, there were 48 such fatalities, representing 53% of all (n=90) unintentional firearm deaths during the same period. The average annual number of fatalities decreased over the last few decades. Very restrictive firearm legislation in Sweden combined with the introduction of a mandatory hunter's exam since 1985 accounted, at least partly, for this finding. Moose hunting accounted for 46% of the fatalities and small game hunting for the remaining cases. The mean age of the victims was 50 years and 96% of them were males; all shooters were males. During moose hunting, most of the victims were mistaken for game, whereas in small game hunting most of the fatalities were related to falls and improper handling of the weapon. Human error was thus the main cause of these fatalities.     

Establishing forensic search methodologies and geophysical surveying for the detection of clandestine graves in coastal beach environments

A 2010 UK police search for a clandestine burial highlighted the need for more information and quantitative data to aid coastal beach searches. This study aimed to address this by establishing relevant forensic search methodologies to aid the search for clandestine coastal burial sites, using the North West English coastline as a search area. A set of parameters were established, including criteria such as tidal range, proximity to vehicular access points and distance from inhabited areas, which may inform forensic searches by prioritising likely locations of clandestine burials. Three prioritised coastal locations were subsequently identified: (1) coastal dunes at Formby, (2) coastal dunes and (3) beach foreshore at Southport, all sites part of the Liverpool City Region in the United Kingdom. At all locations, simulated clandestine graves were hand-dug by spades into which a naked adult-sized, metal-jointed fiberglass mannequin was buried at 0.5 m below ground level. Trial geophysical surveys were then undertaken with the aim of identifying the optimal geophysical instrumentation and technique to deploy in such environments. GPR data showed 450 MHz frequency antennae to be optimal, with significantly poor data obtained from the foreshore area due to saline seawater. Electrical resistivity and magnetic susceptibility surveys were successful in coastal environments in target detection (albeit not in non-vegetated sand dunes), with resistivity fixed-offset configurations deemed optimal. The latter survey successes may be due to the recent disturbed 'grave' rather than the target, which itself is of interest in terms of identifying the most recent clandestine burials.     

Yield and turnover of illicit indoor cannabis (Cannabis spp.) plantations in Belgium

In prosecution, Belgian judiciary currently uses outdated yield figures (28.1g per plant, sold at € 3/g at grower level) for fining illicit indoor cannabis plantations. Using state-of-the-art cultivation techniques, our growth experiments showed that yield is better expressed in g/m(2) cultivated surface area rather than in g per plant, and that yield varies significantly between different cannabis strains. It was found that the lower-bound of the one-sided 95% confidence interval of the yield of an indoor cannabis plantation can be set at 575 g/m(2). Prices and pricing mechanisms were investigated using interviews with respondents selected through snowball sampling. Results reveal that (i) the Belgian cannabis market chain is highly complex; (ii) unit prices are predominantly determined by transaction sizes; but also (iii) a set of product- and socially-related price-fixing mechanisms have an equally important role. At grower level, respondents reported prices for 1 g of dry cannabis buds to range € 3.00-4.25.     

A concept study on identification and attribution profiling of chemical threat agents using liquid chromatography-mass spectrometry applied to Amanita toxins in food

Accidental or deliberate poisoning of food is of great national and international concern. Detecting and identifying potentially toxic agents in food is challenging due to their large chemical diversity and the complexity range of food matrices. A methodology is presented whereby toxic agents are identified and further characterized using a two-step approach. First, generic screening is performed by LC/MS/MS to detect toxins based on a list of selected potential chemical threat agents (CTAs). After identifying the CTAs, a second LC/MS analysis is performed applying accurate mass determination and the generation of an attribution profile. To demonstrate the potential of the methodology, toxins from the mushrooms Amanita phalloides and Amanita virosa were analyzed. These mushrooms are known to produce cyclic peptide toxins, which can be grouped into amatoxins, phallotoxins and virotoxins, where α-amanitin and β-amanitin are regarded as the most potent. To represent a typical complex food sample, mushroom stews containing either A. phalloides or A. virosa were prepared. By combining the screening method with accurate mass analysis, the attribution profile for the identified toxins and related components in each stew was established and used to identify the mushroom species in question. In addition, the analytical data was consistent with the fact that the A. virosa specimens used in this study were of European origin. This adds an important piece of information that enables geographic attribution and strengthens the attribution profile.