Fingerprint identification: advances since the 2009 National Research Council report

Study of the fingerprints of a Spanish sample for the determination of the hand and finger

The individuality and permanence of fingerprints make of them a very useful feature in the identification of individuals. There are now automated computer programmes that allow a quick comparison between a fingermark and a database. However, in order to assess the strength of evidence in fingerprint identification, complementary information on the frequencies of the different morphological features of the dermopapillary ridges is required. This idea is used in this work as a starting point to evaluate the frequencies of the parameters used in the determination of the hand and finger in a large sample of 2600 fingerprints taken from 134 male and 127 female Spanish population. Based on these fingerprints, the frequencies of different categories of the following parameters were obtained: type of pattern, slope of the apex ridge, subtype of two-delta pattern, ridge tracing, major angle, major ridge count, bisector, rotation of the central ridge, assimilation to loops and slant. Moreover, the results have shown that these characters are useful for the determination of the hand in whorls (two-delta pattern) and loops (one-delta pattern), but not for the determination of the finger. The most useful and classificatory parameter when determining the hand of origin of a two-delta fingerprint is the slope of the apex ridge, and for the one-delta pattern, knowing the location of the delta allows the correct estimation of the hand of a fingerprint in more than 93% of the cases. The data presented in this paper are novel and can be used by latent print examiners to improve the statistical basis of their decisions in reaching conclusions.

Toward better AFIS practice and process in the forensic fingerprint environment

Automated Fingerprint Identification Systems (AFIS) are used in forensic operational environments worldwide. Traditionally, these systems are search systems only and have limited workflow to support forensic processes in recommended best-practice approaches. This paper addresses this issue by presenting best practice approaches and processes for AFIS in forensic environments. The discussion is divided into three parts. First, we identify three factors that can impact the performance of AFIS in forensic environments. Second, we discuss the search process and highlight how the National Police of the Netherlands (NPN) strategies to mitigate bias and error in their AFIS workflow. Finally, we briefly discuss other considerations for establishing best-practice. We offer resources for biometric managers and users, providing an overview of the best AFIS practices in forensic environments. We propose the NPN system as a benchmark and aim to foster discussions among AFIS communities to enhance AFIS practices and processes in forensic fingerprint environments.

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 35 years 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.

Anionic polymerization of nonaromatic maleimide to achieve full-color nonconventional luminescence

Nonconventional or nonconjugated luminophore without polycyclic aromatics or extended π-conjugation is a rising star in the area of luminescent materials. However, continuously tuning the emission color within a broad visible region via rational molecular design remains quite challenging because the mechanism of nonconventional luminescence is not fully understood. Herein, we present a new class of nonconventional luminophores, poly(maleimide)s (PMs), with full-color emission that can be finely regulated by anionic polymerization even at ambient temperature. Interestingly, the general characteristics of nonconventional luminescence, cluster-triggered emission, e.g., concentration-enhanced emission, are not observed in PMs. Instead, PMs have features similar to aggregation-caused quenching due to boosted intra/inter-molecular charge transfer. Such a biocompatible luminescent material synthesized from a low-cost monomer shows great prospects in large-scale production and applications, including security printing, fingerprint identification, metal ion recognition, etc. It also provides a new platform of rational molecular design to achieve full-color nonconventional luminescence without any aromatics.

Nonconventional luminophores without extended π-conjugation is a rising star in the area of luminescent materials but continuously tuning the emission color within a broad visible region via rational molecular design remains challenging. Here, the authors present poly(maleimide)s as a new class of nonconventional luminophores with fully tunable room temperature color emission that can be regulated by anionic polymerization

Bayesian multivariate models for case assessment in dynamic signature cases

Dynamic signatures are recordings of signatures made on digitizing devices such as tablet PCs. These handwritten signatures contain both dynamic and spatial information on every data point collected during the signature movement and can therefore be described in the form of multivariate data. The management of dynamic signatures represents a challenge for the forensic science community through its novelty and the volume of data available. Much as for static signatures, the authenticity of dynamic signatures may be doubted, which leads to a forensic examination of the unknown source signature. The Bayes' factor, as measure of evidential support, can be assigned with statistical models to discriminate between competing propositions. In this respect, the limitations of existing probabilistic solutions to deal with dynamic signature evidence is pointed out and explained in detail. In particular, the necessity to remove the independence assumption between questioned and reference material is emphasized.

Layered patterns in nature, medicine, and materials: quantifying anisotropic structures and cyclicity

Various natural patterns-such as terrestrial sand dune ripples, lamellae in vertebrate bones, growth increments in fish scales and corals, aortas and lamellar corpuscles in humans and animals-comprise layers of different thicknesses and lengths. Microstructures in manmade materials-such as alloys, perlite steels, polymers, ceramics, and ripples induced by laser on the surface of graphen-also exhibit layered structures. These layered patterns form a record of internal and external factors regulating pattern formation in their various systems, making it potentially possible to recognize and identify in their incremental sequences trends, periodicities, and events in the formation history of these systems. The morphology of layered systems plays a vital role in developing new materials and in biomimetic research. The structures and sizes of these two-dimensional (2D) patterns are characteristically anisotropic: That is, the number of layers and their absolute thicknesses vary significantly in different directions. The present work develops a method to quantify the morphological characteristics of 2D layered patterns that accounts for anisotropy in the object of study. To reach this goal, we use Boolean functions and an N-partite graph to formalize layer structure and thickness across a 2D plane and to construct charts of (1) "layer thickness vs. layer number" and (2) "layer area vs. layer number." We present a parameter disorder of layer structure (DStr) to describe the deviation of a study object's anisotropic structure from an isotropic analog and illustrate that charts and DStr could be used as local and global morphological characteristics describing various layered systems such as images of, for example, geological, atmospheric, medical, materials, forensic, plants, and animals. Suggested future experiments could lead to new insights into layered pattern formation.

The logical foundations of forensic science: towards reliable knowledge

The generation of observations is a technical process and the advances that have been made in forensic science techniques over the last 50 years have been staggering. But science is about reasoning-about making sense from observations. For the forensic scientist, this is the challenge of interpreting a pattern of observations within the context of a legal trial. Here too, there have been major advances over recent years and there is a broad consensus among serious thinkers, both scientific and legal, that the logical framework is furnished by Bayesian inference (Aitken et al. Fundamentals of Probability and Statistical Evidence in Criminal Proceedings). This paper shows how the paradigm has matured, centred on the notion of the balanced scientist. Progress through the courts has not been always smooth and difficulties arising from recent judgments are discussed. Nevertheless, the future holds exciting prospects, in particular the opportunities for managing and calibrating the knowledge of the forensic scientists who assign the probabilities that are at the foundation of logical inference in the courtroom.