Fingerprint Examiners Research Articles

Jack of all trades, master of one: domain-specific and domain-general contributions to perceptual expertise in visual comparison

Perceptual expertise is typically domain-specific and rarely generalises beyond an expert’s domain of experience. Forensic feature-comparison examiners outperform the norm in domain-specific visual comparison, but emerging research suggests that they show advantages on other similar tasks outside their domain of expertise. For example, fingerprint examiners not only outperform novices in fingerprint comparison, but also in face comparison. Yet, the extent to which their skills generalise is poorly understood. In this study, we investigated the generalisability of perceptual expertise amongst forensic examiners by comparing their performance to novices and other examiners within and outside their area of expertise. We recruited 85 experts from three forensic disciplines (face, fingerprint, and firearms) and asked them to complete four different visual comparison tasks: faces, fingerprints, firearms, and novel-objects. Examiners displayed domain-specific expertise: they outperformed novices and other examiners within their domain of visual comparison expertise. Yet, some of their skill also generalised: examiners also outperformed novices outside their area of expertise. However, while individual differences in examiners’ performance within their domain of experience were associated with their performance in a novel comparison task, they were not related to their performance on tasks outside their expert domain. These results provide key insight into the domain-specific and domain-general contributions of forensic examiners’ perceptual expertise. Forensic expertise lends some generalisable skill to other visual comparison tasks, but best performance is still seen within examiners’ domain of expertise.

UK National Fingerprint Collaborative Exercise 2022-23

In 2022–2023 the Defence Science and Technology Laboratory (Dstl) designed and conducted a two-part fingerprint Collaborative Exercise (CE). The CE focussed on fingermarks contaminated in blood as they provide a complex scenario for forensic units and it involved both fingermark visualisation and comparison elements. Participants were requested to treat the exercise as a major crime submission following internal protocols and were invited to provide comments relating to how the marks were deposited (if appropriate). Overall, forensic units performed well within both parts of the exercise. The exercise highlighted the importance of conducting sequential fingermark visualisation techniques, utilising additional lighting techniques and maintaining detailed notes throughout the fingerprint examination process. The outputs from the CE provided opportunities for forensic units to learn from one another, raise the level of understanding of blood contaminated fingermarks and identify areas of improvement which can be incorporated into internal processes.

Nanostructured assessment of copper oxide for latent fingerprint recognition

Nanotechnology has revolutionized the different fields of forensic science, particularly in the efficient examination of evidence. In this study, we report scalable synthesis of copper oxide (CuO) nanosheets by using hydrothermal method and its exploration in the forensic examination of latent fingerprints. The identification and structural characterization of CuO nanoparticles were carried out using advanced spectroscopic methods such as powder X-ray diffraction (PXRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The stabilization of CuO nanosheets in monoclinic symmetry (space group C2/c) was confirmed through Le Bail refinements. Morphological studies based on scanning electron microscopy (SEM) revealed that the CuO nanosheets exhibit, a rectangular, thin plate like morphology.The applicability of these nanosheets was tested for examining and developing fresh and aged (7 days old) latent fingerprints on dry, non-absorbent substrates using the powder dusting method. The formulation successfully developed sharp and clear fingerprints on various substrates, allowing the second-level details of the fingerprints to be viewed without any background interference. Additionally, these nanosheets are non-hazardous and cost-effective, making them a suitable fingerprint developing agent for a wide range of dry, non-absorbent surfaces recovered from crime scenes.

How often do fingerprint examiners disagree in routine casework?

During routine casework, fingerprint examiners are required to make decisions pertaining to the sufficiency of friction ridge skin impressions. Prior experimental research has established that differences of opinion between examiners are expected, though it is uncertain if these findings are representative of the decisions made during casework. In this study, 5000 job-cards completed by fingerprint experts of the NSW Police Force were scrutinised to track the differences of opinion that occurred between examiners. Experts recorded 19,491 casework decisions, which resulted in 8964 reported identification and inconclusive determinations. Expert decision making was found to be unanimous in 94.8 % of these determinations; 4.6 % involved one expert-to-expert disagreement; and 0.5 % involved two expert-to-expert disagreements. Nil determinations featured more than two expert-to-expert disagreements. Expert-to-expert disagreements occurred in 3.7 % of all identification and inconclusive casework verification decisions. However, verifying experts were more likely to agree with a prior expert’s identification decision, than a prior expert’s inconclusive decision. The observed expert-to-expert identification disagreement rate was 2.0 %, whereas the observed expert-to-expert inconclusive disagreement rate was 12.5 %. Overall, most casework disagreements arose due to subjective differences concerning the suitability of friction ridge skin information for comparison or sufficiency for identification. Experts were more concordant in their decision-making with other experts than with trainees, and approximately three times more likely to disagree with a prior trainees’ identification or inconclusive decision than a prior experts’ identification or inconclusive decision. We assume these differences reflect trainees’ developing proficiencies in assessing the suitability or sufficiency of friction ridge skin impression information. Differences of opinion in casework are expected, which exposes the subjective nature of fingerprint decision-making. Computer-based quality metric and likelihood ratio tools should be considered for use in casework to guide examiner evaluations and mitigate examiner disagreements.

The effects of cognitive bias, examiner expertise, and stimulus material on forensic evidence analysis.

Forensic examiners have come under scrutiny due to high-profile exonerations, highlighting the consequences that contextual bias can have on investigations. Researchers have proposed solutions to reduce the effects of bias including blind testing and redacting task-irrelevant information. Practitioners have concerns over the limitations of some of this research that uses untrained students to examine complex pieces of forensic evidence (e.g., fingerprints) (1; but see 2 for studies including trained experts and/or actual casework). This study sought to (a) examine the effect of contextual bias on examiners' evaluation of forensic evidence by varying the amount of pre-comparison information available to participants, (b) compare student and expert examiners' performance and their vulnerability to contextual bias, and (c) examine the effects of contextual bias on examiners' evaluation of different types of forensic evidence. Expert fingerprint examiners and student participants were presented with varying amounts of pre-comparison case information and compared matching and non-matching fingerprint and footwear impression evidence. Results suggest no effects of blinding examiners from case information or redacting task-irrelevant information. As expected, expert fingerprint examiners were more likely to correctly identify matching fingerprints and correctly exclude non-matching fingerprints than students. However, expert fingerprint examiners were no better than student participants at comparing footwear impression evidence. These findings suggest that sample, stimulus selection, and discipline-specific training matter when investigating bias in forensic decision making. These findings suggest caution when using forensic stimuli with student samples to investigate forensic decision-making and highlight the need for more research on redaction procedures.

Analisis Sisa Radiofarmaka Teknesium-99m MDP Pada Pemeriksaan Sidik Tulang Di Instalasi Kedokteran Nuklir

Bone cancer that has metastasized can be detected through a bone fingerprint examination, which involves the injection of tc-99m with the pharmaceutical Methylene Diphosphate (MDP). Bone prints are often used to trigger possible metastases of cancer to the bone, which is a major health problem for women worldwide. This study aims to activate the described organ uptake and residual radiopharmaceuticals in bone prints using the Region of Interest (ROI) method. The research was conducted on five datasets of patients with breast cancer. The patient received an intravenous injection of tc-99m MDP and, three hours later, underwent a bone fingerprint examination with a gamma camera. The image results from the gamma camera were processed using the ROI technique and analyzed further using statistical methods. The research findings showed that the five patients experienced an average reduction in residual radiopharmaceuticals of 2.965945119 mCi. Several factors, such as examination time, radiopharmaceutical dose, and body metabolism, influence the decay of radioactive activity in the body. The calculation of the absorption percentage for the five patients showed variations between 0.190070697% and 0.3510157519%

The effect of fingerprint expertise on visual short-term memory

Expert fingerprint examiners demonstrate impressive feats of memory that may support their accuracy when making high-stakes identification decisions. Understanding the interplay between expertise and memory is therefore critical. Across two experiments, we tested fingerprint examiners and novices on their visual short-term memory for fingerprints. In Experiment 1, experts showed substantially higher memory performance compared to novices for fingerprints from their domain of expertise. In Experiment 2, we manipulated print distinctiveness and found that while both groups benefited from distinctive prints, experts still outperformed novices. This indicates that beyond stimulus qualities, expertise itself enhances short-term memory, likely through more effective organisational processing and sensitivity to meaningful patterns. Taken together, these findings shed light on the cognitive mechanisms that may explain fingerprint examiners’ superior memory performance within their domain of expertise. They further suggest that training to improve memory for diverse fingerprints could practically boost examiner performance. Given the high-stakes nature of forensic identification, characterising psychological processes like memory that potentially contribute to examiner accuracy has important theoretical and practical implications.

A guide to measuring expert performance in forensic pattern matching

Decisions in forensic science are often binary. A firearms expert must decide whether a bullet was fired from a particular gun or not. A face comparison expert must decide whether a photograph matches a suspect or not. A fingerprint examiner must decide whether a crime scene fingerprint belongs to a suspect or not. Researchers who study these decisions have therefore quantified expert performance using measurement models derived largely from signal detection theory. Here we demonstrate that the design and measurement choices researchers make can have a dramatic effect on the conclusions drawn about the performance of forensic examiners. We introduce several performance models – proportion correct, diagnosticity ratio, and parametric and non-parametric signal detection measures – and apply them to forensic decisions. We use data from expert and novice fingerprint comparison decisions along with a resampling method to demonstrate how experimental results can change as a function of the task, case materials, and measurement model chosen. We also graphically show how response bias, prevalence, inconclusive responses, floor and ceiling effects, case sampling, and number of trials might affect one’s interpretation of expert performance in forensics. Finally, we discuss several considerations for experimental and diagnostic accuracy studies: (1) include an equal number of same-source and different-source trials; (2) record inconclusive responses separately from forced choices; (3) include a control comparison group; (4) counterbalance or randomly sample trials for each participant; and (5) present as many trials to participants as is practical.

Fingerprint Examination by Gender in Healthy Turkish Population

Abstract Background: Dermatoglyphic forensic institutions provide important information that can also be used in the field of anthropology and medicine. To expand the existing data of the Turkish society and increasing literature data on fingerprint. Materials and Methods: This study was conducted with 147 healthy young people. The parameters examined were compared between right and left hands and between genders. The fingerprints were divided into two groups as whorl, loop, arch, and accidental pattern. In addition, “total finger ridge count, absolute finger ridge count, Pattern Intensity Index (PII), Cummins index (CI), Poll index (PI), Dankmeijer index (DI), Volotzkoy index (VI), and Furuhata’s index (FI)” of fingerprints on both hands and right-left hands separately were calculated. Results: In the joint evaluation of 10 fingers in both genders, the most common type was found to be loop pattern. The index data of the Turkish population are as follows (respectively, female and male): PII – 13.2/12.6, CI – 0.1/0.2, PI – 1/1, DI – 11.9/33.3, VI – 132.3/126.7, and FI – 128/133.7. There was no significant difference in the compared parameters between males and females and both hands (P > 0.05). Conclusions: According to the data obtained, the Turkish population data correspond to the Mediterranean subgroup of the European races. Moreover, as seen in this study, ulnar loop density is more common in Eastern countries.

A bimanual comparison of variation in sweat pores with sex and age: a brief dermatoglyphic survey of population in Delhi-NCR

BackgroundPersonal identification using partial fingerprints poses a major challenge in forensic investigations. In light of such restrictions, sweat pore characteristics have shown to be a possible alternative. However, limited research has been done on these due to their minute size. The present study was undertaken with the objective of studying the differences in pore frequency, pore shapes (circular and non-circular), and pore positions (middle and periphery) with respect to sex, bimanual, and age in the population of Delhi-NCR (National Capital Region). As there is no universal approach for defining the evaluation area of pore analysis, we used fingerprint patterns to demarcate a 9mm2 area of analysis. The rolled-inked fingerprints of 200 individuals (100 males and 100 females) belonging to 18-60 years of age were examined using microscopy.ResultsThe obtained data for all prints was analysed and compared with respect to the different variables. The results showed statistically significant bimanual variations for both sexes. In females, all studied pore characteristics except the number of pores at the middle position were significantly higher in the right hand as compared to the left hand. In males, only the number of pores at the peripheral position was significantly higher in the right hand as compared to the left hand. However, no significant differences were observed in pore characteristics between the two sexes and among the different age groups. Moreover, several pore characteristics showed a significant correlation with age in males as compared to females where no significant correlations were observed.ConclusionsSignificant bimanual variations highlighted the potential application of pore characteristics for forensic practice; wherein a fingerprint examiner might determine the probable hand used for the commission of the crime, thereby strengthening the evidentiary value of partial fingerprints. These findings also suggest that the sex and age of an individual cannot be determined by pore characteristics.

Reliability of ordinal outcomes in forensic black-box studies

Forensic science disciplines such as latent print examination, bullet and cartridge case comparisons, and shoeprint analysis, involve subjective decisions by forensic experts throughout the examination process. Most of the decisions involve ordinal categories. Examples include a three-category outcome for latent print comparisons (exclusion, inconclusive, identification) and a seven-category outcome for footwear comparisons (exclusion, indications of non-association, inconclusive, limited association of class characteristics, association of class characteristics, high degree of association, identification). As the results of the forensic examinations of evidence can heavily influence the outcomes of court proceedings, it is important to assess the reliability and accuracy of the underlying decisions. “Black box” studies are the most common approach for assessing the reliability and accuracy of subjective decisions. In these studies, researchers produce evidence samples consisting of a sample of questioned source and a sample of known source where the ground truth (same source or different source) is known. Examiners provide assessments for selected samples using the same approach they would use in actual casework. These studies often have two phases; the first phase comprises of decisions on samples of varying complexities by different examiners, and the second phase involves repeated decisions by the same examiner on a (usually) small subset of samples that were encountered by examiners in the first phase. We provide a statistical method to analyze ordinal decisions from black-box trials with the objective of obtaining inferences for the reliability of these decisions and quantifying the variation in decisions attributable to the examiners, the samples, and statistical interaction effects between examiners and samples. We present simulation studies to judge the performance of the model on data with known parameter values and apply the model to data from a handwritten signature complexity study, a latent fingerprint examination black-box study, and a handwriting comparisons black-box study.

Expertise of fingerprints contaminated with particles of nuclear material collected from the radiological crime scene

For the successful investigation of crimes involving the MNR, it is important to examine and evaluate all traces and material evidence collected from the crime scene, which require special handling conditions as they are contaminated with radionuclides. This study establishes the possibility of examining both NRM microparticles by SEM-RMA and fingerprints by cyanoacrylate fumigation, on common objects with different surfaces. It is shown that the most complete results can be obtained by analyzing the samples on conductive objects. The surfaces of objects on which limited results can be obtained are determined, as well as the surfaces on which the examination of microparticles and fingerprints is not possible.

Précis of Thinking and Perceiving

Thinking and Perceiving defends the claim that thought not only affects perceiving, thought improves perceiving. It thus defends a malleable architecture of the mind, opposite strong modularist views that claim that perception is informationally encapsulated and thus cognitively impenetrable. The argument for this view centers around cases of perceptual expertise. Experts in a wide variety of domains—radiology, birdwatching, elite athletics, fingerprint examination—have been empirically studied using behavioral, neural-physiological, and computational methods. This convergence of evidence is best explained in terms of cognitively sensitive perceptual improvements. And these improvements amount to epistemic virtue, where the virtue is partly resident in perception and credited to the perceiving agent. The view has far-reaching implications for a wide range of issues, including the epistemology of perception, the contents of perception, theory-ladenness in science and social perception, understanding and self-understanding, and aesthetic taste.

Understanding the challenges of disaster victim identification: perspectives of Australian forensic practitioners.

Disaster victim identification (DVI) is an important process in the aftermath of disasters to provide answers for the families and communities of victims. Australian forensic practitioners contribute to such processes internationally under difficult post-disaster circumstances. The aim of the study was to better understand the challenges experienced by forensic practitioners in international DVI operations. Participants (N = 20) included DNA analysts, fingerprint examiners, forensic odontologists, forensic pathologists, and mortuary technicians who had experience in DVI operations. Participants were interviewed about their experiences and perceptions of the challenges of DVI. The findings provide valuable insights into the types of DVI operations in which Australian forensic practitioners have been involved internationally. Thematic analysis of interview data resulted in five main themes: the post-disaster work environment; DVI management and processes; political and financial influences; teamwork in intercultural and interdisciplinary contexts; and confronting the emotional realities of DVI work. The analysis highlights the interrelated challenges associated with DVI operations in international contexts. Practitioners also provided suggestions for improvement, which generally aligned with the themes and reflected an ethos of learning and continuous improvement in DVI. Further research on education and training and capacity-development initiatives is warranted.

Finding the perfect match: Fingerprint expertise facilitates statistical learning and visual comparison decision-making.

Forensic feature-comparison examiners compare-or "match"-evidence samples (e.g., fingerprints) to provide judgments about the source of the evidence. Research demonstrates that examiners in select disciplines possess expertise in this task by outperforming novices-yet the psychological mechanisms underpinning this expertise are unclear. This article investigates one implicated mechanism: statistical learning, the ability to learn how often things occur in the environment. This ability is likely important in forensic decision-making as samples sharing rarer statistical information are more likely to come from the same source than those sharing more common information. We investigated 46 fingerprint examiners' and 52 novices' statistical learning of fingerprint categories and application of this knowledge in a source-likelihood judgment task. Participants completed four measures of their statistical learning (frequency discrimination judgments, bounded and unbounded frequency estimates, and source-likelihood judgments) before and after familiarization to the "ground-truth" category frequencies. Compared to novices, fingerprint examiners had superior domain-specific statistical learning across all measures-both before and after familiarization. This suggests that fingerprint expertise facilitates domain-specific statistical learning-something that has important theoretical and applied implications for the development of training programs and statistical databases in forensic science. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Unusual fingerprint patterns in humans: implications for forensic casework and fingerprint research

The tenacity of the fingerprint evidence for the identification of criminals has been well documented, but none of the research work so far focussed on unusual prints. Therefore, in the present study, we attempted to define rarely encountered fingerprints in a human population. Our purpose was to explore unusual pattern types on the finger balls and compare these with commonly occurring and classifiable pattern types. Furthermore, we discuss the occurrence of unusual fingerprints in both the sexes with reference to the finger digits. The study was conducted on 512 participants aged between 18 and 35years from two ethnic groups of North India. A total of 5120 fingerprints from each digit of the 512 individuals were obtained. The fingerprints were analysed for the pattern types based on Henry's classification. Patterns that did not fall in the prescribed category as per the definition of the published finger pattern types were identified as unusual fingerprints. We found an incidence of unusual prints of 0.21% and describe these based on a comparison with the general pattern types according to Henry's classification. We describe eleven unusual fingerprint patterns, formulating categories that may aid in the individualisation process. The proposed new nomenclature of these unusual fingerprints may assist forensic scientists and fingerprint examiners in better understanding and labelling of similar patterns in forensic cases. Our research may also influence the general forensic science community and biological anthropologists in making population standards pertaining to different types of fingerprints in various population groups and their genetic and familial relationships.

Research on the local regional similarity of automatic fingerprint identification system fingerprints based on close non‐matches in a ten million people database—Taking the central region of whorl as an example

The local regional similarity of fingerprints has always been a hot issue in the field of fingerprint research. With the increasing size of ten-print databases, the appearance of close non-matches (CNMs) in automatic fingerprint identification system (AFIS) candidate lists has attracted increasing attention from forensic science departments worldwide. In this study, three categories (high-, medium-, and low-level) of standards for CNMs were established and 60 whorl samples were marked with different numbers of minutiae to explore the occurrence and influencing factors of CNMs in AFIS candidate lists based on a ten million people database. The results showed that all prints could be found with their corresponding CNMs. The average occurrence rate of CNMs for every query was 52.7% in the top 100 lists, and the most similar CNM was exactly the same in the local area of 12 coincidence points. CNMs appeared more in the middle and lower parts of the central region of the whorl. Moreover, shorter C2C distances and the same finger number and hand led to more CNMs being inspected. CNMs with higher similarity required a more extensive regional area and smaller minutiae density. We concluded that CNMs have a high occurrence rate in large-scale databases and many factors are closely related to them. Fingerprint examiners and researchers need to strengthen their understanding of CNMs to avoid the occurrence of misidentification like the Madrid bombings.

Not all identification conclusions are equal: Quantifying the strength of fingerprint decisions

In the pattern comparison disciplines, forensic practitioners evaluate two impressions with respect to the same-source and different-sources propositions. The results are communicated using a pre-determined conclusion scale, and in the friction ridge discipline Identification is typically the highest category on the scale for reporting evidence supporting the same source proposition. Although error rates have been measured in most disciplines, there are no widespread quantitative approaches and therefore most conclusions rely on subjective human evaluations. The current work uses articulation decisions provided by fingerprint examiners in error rate studies to produce a quantitative likelihood ratio measure that characterizes the strength of the support for the two propositions. We use an ordered probit model to summarize the distribution of responses of examiners who participated in error rate and validation studies. We then aggregate the data for all image pairs in a database to construct a set of likelihood ratios based on the ratio of the two strength-of-support values. We find that these values are modest relative to values typically produced by DNA analysis or implied by current fingerprint articulation language. The technique can be applied to any pattern comparison discipline for which error-rate data is available, and therefore can be used to appropriately weigh the evidence from different disciplines.

A method for quantifying individual decision thresholds of latent print examiners

In recent years, ‘black box’ studies in forensic science have emerged as the preferred way to provide information about the overall validity of forensic disciplines in practice. These studies provide aggregated error rates over many examiners and comparisons, but errors are not equally likely on all comparisons. Furthermore, inconclusive responses are common and vary across examiners and comparisons, but do not fit neatly into the error rate framework. This work introduces Item Response Theory (IRT) and variants for the forensic setting to account for these two issues. In the IRT framework, participant proficiency and item difficulty are estimated directly from the responses, which accounts for the different subsets of items that participants often answer. By incorporating a decision-tree framework into the model, inconclusive responses are treated as a distinct cognitive process, which allows inter-examiner differences to be estimated directly. The IRT-based model achieves superior predictive performance over standard logistic regression techniques, produces item effects that are consistent with common sense and prior work, and demonstrates that most of the variability among fingerprint examiner decisions occurs at the latent print evaluation stage and as a result of differing tendencies to make inconclusive decisions.

The interpretation of forensic conclusions by professionals and students: Does experience matter?

Are professionals better at assessing the evidential strength of different types of forensic conclusions compared to students? In an online questionnaire 96 crime investigation and law students, and 269 crime investigation and legal professionals assessed three fingerprint examination reports. All reports were similar, except for the conclusion part which was stated in a categorical (CAT), verbal likelihood ratio (VLR) or numerical likelihood ratio (NLR) conclusion with high or low evidential strength. The results showed no significant difference between the groups of students and professionals in their assessment of the conclusions. They all overestimated the strength of the strong CAT conclusion compared to the other conclusion types and underestimated the strength of the weak CAT conclusion. Their background (legal vs. crime investigation) did have a significant effect on their understanding. Whereas the legal professionals performed better compared to the crime investigators, the legal students performed worse compared to crime investigation students.