Examination of the steps leading up to the physical developer process for developing fingerprints

This is a systematic study that examines several acid prewashes and water rinses on paper bearing latent prints before its treatment with a silver physical developer. Specimens or items processed with this method are usually pretreated with an acid wash to neutralize calcium carbonate from the paper before the treatment with a physical developer. Two different acids at varying concentrations were tested on fingerprints. Many different types of paper were examined in order to determine which acid prewash was the most beneficial. Various wash times as well as the addition of a water rinse step before the development were also examined. A pH study was included that monitored the acidity of the solution during the wash step. Scanning electron microscopy was used to verify surface calcium levels for the paper samples throughout the experiment. Malic acid at a concentration of 2.5% proved to be an ideal acid for most papers, providing good fingerprint development with minimal background development. Water rinses were deemed unnecessary before physical development.     

A novel chitosan/tripolyphosphate/L‐lysine conjugates for latent fingerprints detection and enhancement

Most chemical and physical methods employed in visualizing latent marks have shown detrimental effects on human health and, therefore, some research groups have directed their attention to the utilization of various (bio)polymers with the aforementioned purpose. Although chitosan is widely used in medicine, pharmacy, food, and drug delivery systems, there are very few studies that address this biopolymer utilization in forensic applications, such as the detection of latent fingerprints. We used chitosan crosslinked with sodium tripolyphosphate and conjugated with L‐lysine to enhance the visualization of latent fingerprints, due to its ability to interact with fingerprint sweat residues. These conjugates were prepared using different (w/w) amounts of chitosan and tripolyphosphate (6/1; 4/1; 1/1; 1/4; and 1/6), and those with the most promising results (i.e., 6/1 formulation) were investigated in detail. Fourier transform infrared (FT‐IR) spectroscopy confirmed interactions between components of the systems. Optical microscopy and scanning electron microscope (SEM) analysis showed that prepared powder formulations were uniform in size and confirmed that chitosan/tripolyphosphate/lysine conjugates bind easily to the sweat and lipid residues present in the latent fingerprints. The testing of prepared conjugates demonstrated the potential of these systems as bio‐based powder substitution for commercially available powders.     

Visualising the past – An evaluation of processes and sequences for fingermark recovery from old documents

This study aimed to collect data on the effectiveness of most of the fingermark visualisation reagents currently used on porous surfaces on fingermarks aged for up to 90?years, significantly extending the timescales for which such information exists. A limited subset of the variables associated with processing of old fingermarks was explored, with a focus on the use of 1,8 diazafluoren-9-one (DFO), 1,2-indandione, ninhydrin, and physical developer. These techniques were used in sequence on batches of cheques between 11 and 32?years old, and on documents dating from the 1920s and 1940s. The potential for applying a physical developer enhancement process (blue toning) as the final step in the sequence was also explored. The benefits of using processing sequences on porous items were clearly demonstrated, with all processes in the sequence adding value in terms of additional marks found on the cheques up to 32?years old. In addition, physical developer was found to be capable of developing fingermarks up to 90?years old, whereas the amino acid reagents appear less effective on documents of 70?years and older. An experimental physical developer formulation with reduced environmental impact was found to be as effective as the existing process in these experiments. Blue toning was found to visualise an additional 10–25% of marks, and its wider use after silver-based deposition processes is recommended based on the evidence from this study.     

A one-step fluorescent detection method for lipid fingerprints; Eu(TTA)3.2TOPO

This paper describes the development of a one-step fluorescent lipid reagent that involves europium chelates whose generic formula can be represented as europium(organic ligand)3.2(synergic reagent). An optimized formulation is presented and a comparison with physical developer was conducted which showed the new technique to be very good when fresh fingerprints were recovered but inferior to physical developer on aged prints (over a week). In addition, the compatibility of the technique with sequential methods such as ninhydrin and DFO is reported. The experimentation, results and chemical formulation of this study were presented to delegates of the International Symposium on Fingerprint Detection and Identification held in Israel in June 1995. Prior to that a patent application had been made.     

Use of gold nanoparticles as molecular intermediates for the detection of fingermarks

Among the numerous methods dedicated to the detection of latent fingermarks, the MultiMetal Deposition (MMD) offers, as a main advantage, the ability to be applied on a great number of porous and non-porous surfaces, e.g., paper, plastic, glass, latex, and polystyrene, even if wetted. While considered as a powerful and sensitive technique, MMD is often neglected, mainly because of operational limitations (siliconized vessels, restrictive pH domain, numerous immersion baths, ...). In this contribution, we propose a modification of the standard MMD method so that the procedure is simplified with a number of baths reduced to a minimum. To reach this goal, it was necessary to obtain a fully operable solution which could detect fingermarks in a single step. We chose to take advantage of the molecular recognition mechanisms by functionalizing the gold nanoparticles with a molecular host able to bind itself to gold while keeping the ability to trap molecules in solution. Cyclodextrins were chosen as they can be easily chemically modified to offer gold-binding abilities. Moreover, they are widely used as hosts for various molecular guests (dyes, luminescent molecules, ...). This new formulation has been tested on three different surfaces to attest the feasibility of this strategy. Successful results were obtained with detailed fingermarks offering a good contrast to allow their identification without the need to enhance the results (such as with a physical developer). If the new formulation behaves very similarly to the old one, in terms of experimental conditions, it offers the additional advantage to develop fingermarks after immersing them in only one bath. The goal is thus reached.     

A comparison of multi-metal deposition processes utilising gold nanoparticles and an evaluation of their application to 'low yield' surfaces for finger mark development

This paper reports a comparison of the effectiveness and practicality of using different multi-metal deposition processes for finger mark development. The work investigates whether modifications can be made to improve the performance of the existing process published by Schnetz. Secondly, we compare the ability of different multi-metal deposition processes to develop finger marks on a range of surfaces with that of other currently used development processes. All published multi-metal deposition processes utilise an initial stage of colloidal gold deposition followed by enhancement of the marks with using a physical developer. All possible combinations of colloidal gold and physical developer stages were tested. The method proposed by Schnetz was shown to be the most effective process, however a modification which reduced the pH of the enhancement solution was revealed to provide the best combination of effectiveness and practicality. In trials comparing the modified formulation with vacuum metal deposition, superglue and powder suspensions on surfaces which typically give low finger mark yields (cling film, plasticised vinyl, leather and masking tape), the modified method produced significantly better results over existing processes for cling film and plasticised vinyl. The modified formulation was found to be ineffective on both masking tape and leather. It is recommended that further tests be carried out on the modified multi-metal deposition formulation to establish whether it could be introduced for operational work on cling film material in particular.     

Role of Nanomaterials for Forensic Investigation and Latent Fingerprinting—A Review

The imminent nanotechnology and progressive instrumentations together have vast applications in the field of forensic science. Few prominent examples are gold nanoparticles for improvising the efficiency of polymerase chain reaction and atomic force microscopy for examining ink and bloodstains. Characteristics like distinct ridge details of fingerprints could be obtained by applying different nanoparticles such as silver, zinc oxide, silicon dioxide, aluminum oxide, gold (with silver physical developer), europium, fluorescent carbon, and amphiphilic silica on a range of object surfaces, and among all, gold is most commonly used. Fingerprint is considered noteworthy evidence in any crime scene, and nano-based techniques hold immense future potential in fingerprint investigations. Therefore, this paper focuses on the applications of nanoparticles in developing and detecting the latent fingerprints.     

Enhancement of microcrystalline identification of gamma-hydroxybutyrate

An enhancement of the microcrystalline test for the detection of gamma-hydroxybutyrate (GHB) is described. The original test used a silver/copper reagent which consisted of 0.1 g of silver nitrate and 0.1 g of copper nitrate in 10 mL water. The enhanced test utilizes lanthanum nitrate in place of copper nitrate. A detection limit of 0.5 mg/mL was achieved and the visual discrimination was improved because of larger sized crystals. Transient crystals were observed between 0.1 and 0.4 mg/mL. Silver nitrate alone appeared to be suitable for GHB detection but was not specific as other hydroxyl acids, such as glycolic acid, produced a similar crystal pattern. Tests conducted on chemical precursors of GHB and substances with similar biological activity highlight the specificity of the enhanced test. The reagent is therefore selective and sensitive for GHB in aqueous solutions. However, in beverage testing, crystal formation appeared to be inhibited for some drinks. Citric acid was identified as a possible interference depending on its concentration relative to GHB.     

Women's motives for violent and nonviolent behaviors in conflicts

Drawing from past research on women's motives for intimate partner violence (IPV) perpetration, correlates of women's perpetration, and correlates of nonviolent conflict, we created a scale containing 125 possible motives, representing 14 broad domains (e.g., self-defense, retaliation). Participants were an ethnically diverse sample of women who had perpetrated no physical IPV against their current partner (n = 243), threats but not physical IPV (n = 70), nonsevere physical IPV (n = 193), and at least one act of severe (e.g., choke) physical IPV (n = 93). An exploratory factor analysis yielded a seven-factor solution, representing Partners' Negative Behaviors, Increase Intimacy, Personal Problems, Retaliation, Childhood Experiences, Situation/Mood, and Partners' Personal Problems. Differences by women's IPV perpetration and race and/or ethnicity were tested with means representing these seven factors and a computed variable representing self-defense. Although motives differed by perpetration type, main effects for Partners' Negative Behavior, Personal Problems, Retaliation, and Childhood Experiences were modified by interactions, suggesting ethnicity should be considered when developing interventions.     

An Analysis of Miranda Warnings and Waivers: Comprehension and Coverage

Miranda warnings enshrine the constitutional rights of custodial suspects against self-incrimination. However, the wording and sentence complexity of Miranda warnings and waivers vary dramatically from jurisdiction to jurisdiction. This study is the first extensive investigation of Miranda warning variations examining 560 Miranda warnings from across the United States. With Flesch-Kincaid reading comprehension as a useful metric, Miranda warnings varied from very simple comprehension (i.e., grade 2.8) to requiring postgraduate education. Miranda warnings are composed of five components (e.g., silence and evidence against you); marked variations were also observed in the comprehensibility of individual components. On average, the Miranda warning component on "continuing rights" requires a reading comprehension level six grades higher than the comparatively simple expression of the right to silence. Similar analyses were conducted on Miranda waivers. The content of these warnings differed on such issues as communicating (a) when access to an attorney would be granted (e.g., 45.9% specified only "during questioning") and (b) explicitly that indigent legal services were free (e.g., 31.8% directly informed suspects). Finally, the study identified representative Miranda components at different levels of reading comprehension as a template for further research.     

Electrically conductive adhesives,thermally conductive adhesives and UV adhesives in data extraction forensics

Recent publications underline the interest of using polymers in microelectronics (Li and Wong, 2006a; Cui et al., 2014). Polymers are the ideal interconnect alternative to solder materials containing lead. Electrically Conductive Adhesives [ECAs] (Li and Wong, 2006b), Thermally Conductive Adhesives (TCAs) (Felba et al., 2011) and UV Adhesives (UVAs) (Asif et al., 2005) mainly consist of a polymeric resin (epoxy, silicon, polyurethane or polyimide) that provides physical and mechanical properties such as adhesion, mechanical strength while containing metal fillers (silver, gold, nickel or copper) that conduct electricity (Luo et al., 2016). Currently it is possible to find really cheap polymeric resin. Using these resins for digital forensic purposes is the focus of this paper, that we demonstrate in a hardware reverse engineering prototype case study.When considering new mobile devices, such as secure phones, it is often necessary to spy communication and perform numerous tests on the memory (e.g. by changing some bytes) to understand or modify the implemented security mechanisms (manipulate system time, locate password hashes, observe artefacts of implemented security algorithms, etc.). Traditional techniques use either laser attacks/probing (chip on) or soldering/read/re-soldering (chip off/on) (Heckmann et al., 2016, Jongh, 2014). These two techniques are unsuitable for repeated operations requiring many readings/changes/injections. This paper describes a concrete case study using adhesive properties complementary to chip on and chip off methods.We present the steps using different properties of adhesives (ECA, TCA, UVA) that we will lead to the realisation of a prototype particularly suitable for the repeating of the read phases/changes/injections necessary for reverse engineering secure mobile devices.     

手印显现物理显影液的研究

物理显影液是渗透性客体上富脂手印的一种有效显现方法.本文就物理显影液显现手印的原理、方法、显现手印类型、显现客体类型、操作注意事项以及影响显现效果的各种因素作了一些探讨.     

Styryl dye coated metal oxide powders for the detection of latent fingermarks on non-porous surfaces

Conventional fingermark powders rely on contrast induced by absorption/reflection (e.g. black powder) or luminescence in the visible region (e.g. Blitz Green(?)). In most cases, these powders provide sufficient contrast; however, in some circumstances surface characteristics can interfere with the visualisation of powdered fingermarks. Visualisation in the near infra-red (NIR) region, however, has been shown to eliminate interferences commonly encountered in the visible region. In this study, a mixture of rhodamine 6G and the NIR laser dye styryl 11 (STaR 11) was coated onto an aluminium oxide nanopowder and then mixed with silver magnetic powder to develop and visualise fingermarks in the NIR. When compared to Blitz Green(?), it was determined that the STaR 11 magnetic powder was better suited for marks deposited on textured surfaces and for older marks, whereas Blitz Green(?) performed better on smooth glossy surfaces. The ability of the STaR 11 mixed dye formulation to be visualised in both the visible and NIR regions also provides a significant advantage over conventional luminescent fingermark powders.     

The reliability of eyewitness identification

This study examines the effects of 14 estimator variables (e.g., disguise of robber, exposure time, weapon visibility) and system variables (e.g., lineup instructions, exposure to mugshots) on a number of measures of eyewitness performance: identification accuracy, choosing rates, confidence in lineup choice, relation between confidence and identification accuracy, memory for peripheral details, memory for physical characteristics of target, and time estimates. Subjects viewed a videotaped reenactment of an armed robbery and later attempted an identification. Characteristics of the videotape and lineup task were manipulated. Prominent findings were as follows: identification accuracy was affected by both estimator and system variables including disguise of robber, weapon visibility, elaboration instructions, and lineup instructions. Memory for peripheral details was positively correlated with choosing on the identification task but negatively correlated with identification accuracy.     

An examination of stress hardiness, dysphoria, and anger among police recruits exposed to stressful police academy training

This study examined whether stress hardiness moderates the relationship between stress and anger during stressful police academy training. It was hypothesized that stress hardiness alters the strength of the relationship between stressful circumstances and anger. The study of stress resistance is an important area of study as stress has been linked to behavioral problems (e.g., absenteeism from work), emotional problems (e.g., depression), and physical problems (e.g., coronary heart disease). This research was conducted as part of the doctoral dissertation requirements of Billy J. James at Walden University, Minneapolis, MN     

Investigations into factors affecting the cascade developer used in ESDA--a review

The Electrostatic Detection Apparatus (ESDA) is a technique most commonly used for the visualisation of indented impressions on questioned documents. This work investigates some of the variables which are known to affect the results of ESDA and some variables which have, as yet, not been addressed. The investigation of variables included: examining the effects of different levels of indentation on different qualities of paper, chronological aging of cascade developer and the effects of repeated use of cascade developer on both the quality of results and the glass beads themselves, the effects of storage of cascade developer in a humidified environment and finally the effects of variation on the image development time. Results indicate that chronological aging of cascade developer does not have a negative effect on the quality of results and a 200 g portion of cascade developer will give good quality results for up to 30 traces before the quality will begin to deteriorate. Humidification of the cascade developer appears to have no advantages over storage in a normal environment and, in fact, the toner is lost sooner with humidification. The surface of the glass beads are affected through repeated use of cascade developer and appear to become visually smoother which may lead to a loss of attraction between them and the toner particles.     

物理显影液显现渗透客体表面血潜手印方法研究

目的　建立了一种物理显影液显现潮湿或者浸泡渗透客体表面血潜手印的新方法。方法　把检材浸泡在配制好的物理显影液中 ,还原的银粒子吸附在血潜手印部位显现出手印纹线。结果　显现出手印纹线为黑灰色 ,纹线连贯 ,反差明显。结论　物理显影液能够有效地显现出潮湿或者浸泡后手渗透客体表面血潜手印。     

Fetal Alcohol Spectrum Disorder (FASD) and the Role of Family Court Judges in Improving Outcomes for Children and Families

Fetal Alcohol Spectrum Disorder (FASD) is a physical disability that is 95% underdiagnosed and 40 times over‐represented in juvenile justice. Prenatal alcohol and other drug exposure causes brain damage that affects behaviors, e.g., poor judgment, impulsivity, difficulty learning from experience, and difficulty understanding consequences, leading to multiple diagnoses such as Attention Deficit Disorder, Conduct Disorder, Oppositional Defiant Disorder and Emotionally Disturbed. FASD is an invisible physical disability; most people with FASD have no observable physical characteristics. The courts are in an important position to increase awareness of this problem by simply asking whether FASD is a factor that needs to be considered. The purpose of this article is to support increased recognition and efficacy of services for people with FASD in the legal system. Sections include: (1) Overview of FASD diagnostic criteria and current terminology; (2) Exploration of FASD as a physical disability with behavioral symptoms; (3) Case example illustrating common patterns of behaviors in children and adults with FASD without identification and improved outcomes following identification and implementation of appropriate treatment; and (4) Recommendations for family court judges.     

Reconsidering discrimination grounds in the data economy: An EU comparison of national constitutions

The principle of equal treatment (i.e., all people have the right to be treated equally) is protected by non-discrimination provisions in national constitutions across the EU as well as the EU Charter of Fundamental Rights (CFEU). These provisions specify which grounds (e.g., gender, race, religion) are prohibited to use as the basis for making decisions on people, such as offering a person a job. In the data economy, in which large amounts of personal data are collected and analyzed, it has become possible to make decisions on people on the basis of all kinds of grounds, also grounds that are not protected in anti-discrimination law (e.g., zip code, shoe size, wealth). Even though mostly unintentional, patterns revealed by sophisticated data analysis can turn out to be discriminatory, either directly or indirectly. Particularly indirect discrimination (i.e., discrimination by proxy) can be hard to discover and enforce. From a substantive perspective, these technological developments also raise the question which discrimination grounds should be protected, since discrimination grounds are in flux and not harmonized across the EU. In this paper, through legal comparison, discrimination grounds across EU national constitutions and the CFEU are compared, to identify overlaps and differences. This overview is then used to start the discussion on the extent to which current legislation is still appropriate in the data economy or should perhaps be reconsidered.     

Detection of latent fingerprints by the use of silver nitrate

Silver nitrate has been an established agent for the detection of latent fingerprints for some 120 years, and it was one of the few reagents suitable for use on porous surfaces until ninhydrin was introduced in forensics. The method is based on the reaction of silver ions with chlorides in the fingerprints, which are visualized in brown, violet or black. The literature describes many variations of the procedure, but the information provided is often vague and imprecise. The purpose of this study was to show whether this method can also be used on modern types of paper and how it should be applied. The results of the tests showed that silver nitrate solutions do work also on modern papers, but that they cannot be recommended as a standard, because the appearance of the prints and the paper background can strongly change in the course of time. The findings also do not justify the use of methanol-containing silver nitrate solutions in contrast to the variations based on water. For reasons of occupational safety, methanol, which is classified as poisonous, should not be used. The silver nitrate method may be taken into consideration, however, e.g. after the application of ninhydin, if there are hints that the potential fingerprints are not too old, have not been affected by moisture and if there are clues that the perpetrator perspired strongly while causing the prints.