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.

Assessment of gunshot residue detection on a large variety of surfaces by portable LIBS system for crime scene application

The application of Laser-Induced Breakdown Spectroscopy (LIBS) in forensic science has garnered increasing attention. The ability to perform real-time, on-site analysis of Gunshot Residue (GSR) particles and potential elements originating from bullets or projectile cores on various surfaces holds the potential to assist in resolving firearms-related cases. This includes facilitating trajectory determination by locating distinct impact points and identifying the types of ammunition used. This study evaluates the utilization of a portable LIBS device for ballistic forensic purposes. Additionally, it focuses on the assessment of potential false positives and false negatives arising from the different materials where the shots have been fired. Since the system performs laser ablation of both surface particles and the substrate, it emphasizes the importance of conducting preliminary screening in an area with the same composition as the impact zone to minimize potential false positives during direct surface analysis. Furthermore, the results demonstrate the capability to detect the constituent elements of characteristic gunshot residue particles (GSR particles): lead (Pb), antimony (Sb), and barium (Ba) adhering to bullets, as well as the principal elements composing the jacket or core of the projectile: lead (Pb), copper (Cu), and zinc (Zn) through direct analysis, without the need for a sampling kit, on different surfaces such as walls, furniture, or fabrics. Analyses conducted a month after the shots were fired indicate the potential for finding residues in the vicinity of the bullet hole. Analyses conducted a month after the shots were fired indicate the possibility of finding residues in the area around the bullet hole.

Assessing the shooting distance of lead-free ammunition regardless of composition using Laser Induced Breakdown Spectroscopy

At present, it is challenging to accurately determine firearm shooting distances in the case that lead-free ammunition is involved, largely because different manufacturers use different primer compositions. Laser-induced breakdown spectroscopy (LIBS) allows the simultaneous detection of multiple elements with high sensitivity and so may represent a solution to this problem. Previous studies have, in fact, demonstrated that LIBS can be used to determine shooting distances when working with gunshot residues from conventional ammunition based on scanning fabric surfaces. The present study confirms that the shooting distance can be ascertained using LIBS to detect copper originating from the ammunition casing and projectile but not the primer on fabric surfaces. This estimation can be performed regardless of the primer composition of lead-free ammunition.

Key points

Evaluation of gunshot residue from lead-free ammunition using scanning electron microscopy-energy dispersive X-ray analysis indicated that 40% of the particles contained copper.The iForenLIBS system allowed the detection of copper-containing particles on fabric surfaces after firing at different distances with high sensitivity.Laser-induced breakdown spectroscopy can determine the shooting distance of lead-free ammunition through copper detection even in ammunition that does not used this element in the primer.This technique can generate density maps allowing the evaluation of short, medium, and long-range shooting distances.

Interpopulational differences in the frequency and distribution of delta types

The classification of the main pattern types, arch, loop and whorls, is based on the number and location of deltas or triradii, which are areas defined by the confluence of three ridge systems carrying different directions on the fingerprint. Despite being areas that give place to an important morphological variability, their study has only been approached from the quantitative point of view, in relation to the number with which they appear per finger, hand, or individual (intensity pattern), and their sexual and population differences; while the qualitative aspects have not been evaluated so far. The following paper aims to study and analyze the qualitative variability, both intra and interpopulation, of the frequency of occurrence of the different types of deltas or triradii, in four fingerprint samples from males of different population origin: 100 individuals from China, 100 individuals from Colombia, 100 individuals from Nigeria and 100 individuals from Romania, which has meant the analysis of 4000 fingerprints. For this purpose, the classification of 24 types used by the Scientific Police and Criminalist Departments of the Guardia Civil of Spain has been employed. The results obtained showed the non-equiprobability of the frequency distribution of the different delta types in the four populations. In all cases, sunk open total deltas (Hat), sunk open total with point (Hat(p)) and tripod long (Tl) were the most frequent types, while the sunk closed total with point (Hct(p)) had the lowest frequency. Furthermore, for the first time, interpopulation differences in the frequency distribution of different types of deltas have become noticeable. The data provided in this paper are a pioneer in the field of dactyloscopy and can be used as a reference by the departments of criminalistics of the different countries for the estimation of the scientific value of the evidence in dactyloscopy.

Fingerprints identification on 3000 year old Egyptian mummies

The Djehuty Project (Dra Abu el-Naga; Luxor, Egypt) contains a reused burial chamber, UE165. The human remains include 6 disarticulated, mummified human digits, of which five have very well-conserved prints. The most plausible dating is the Twenty-Second Dynasty (945-715 BCE). High resolution photographs were taken of these and studied in order to identify the main pattern, delta types and minutiae, ridge density and ridge breadth. First, however, a contemporary mummified body was studied in order to calculate the percentage of contraction that can occur in mummified digit tissue. The remains consisted of 4 fingers (a thumb, two index fingers and a middle finger) and a hallux toe, all from the right side, indicating that they came from at least two different people. As regards sex, all the fingers presented values typical of females. Estimated age ranged from 10.62 (middle finger) to 16.25 (thumb) years old, within the sub-adult category. The individual's height was estimated for all the fingers, obtaining values between 135.87 cm for the middle finger and 162.60 cm for the thumb. With regard to the possible ancestral origins of the remains, the type of delta o triradius identified presents high frequencies in contemporary Nigerian and Romanian populations. These results demonstrate that it is possible to work with fingerprints as much as 3,000 years old. It has been possible to identify the main patterns and the minutiae with a precision that exceeds the numeric standard -12 minutiae- currently applied in many countries for forensic identification.

Distribution of the minutiae in palmprints: Topological and sexual variability

Palmprints have been systematically less studied than fingerprints, despite being of great use in the identification process. In Spain, they were not included in Automated Fingerprint Identification Systems (AFIS) until 2009. Very few investigations performed within the field of palmprints have assessed the sexual and population variability of the number and distribution of minutiae on its surface, despite the fact that these particularities are the basis for personal identification in forensic science. That is why a study was conducted to assess total, bimanual, and sexual density per morphological regions (superior or distal, thenar, and hypothenar) and per counting areas of 1 cm² on 120 palmprints obtained from 30 male and 30 female individuals of Spanish nationality. Also, the frequency in the location of each type of delta or triradius (a, b, c, d, and t) per count area was calculated. Results have shown a topological variability in the distribution of the density of minutiae, which is similar between sexes and a specular effect between both hands. The most frequent locations of the deltas coincide with areas of high minutiae density. It has also been shown that there are sexual differences in the total number of minutiae, which cannot be due to sexual dimorphism in adult hand size, since minutiae are established at an early stage of fetal development and their number will not change during later postnatal growth. These differences can only be attributed to genetic factors related to sexual determination.

Fingerprint ridge density in the Argentinean population and its application to sex inference: A comparative study

Fingerprint ridge density (RD) is known to vary according to sex and population, and such variation can be used for forensic purposes. The aim of this study was to analyze the fingerprint RD of two samples of the Argentinean population in order to assess their topological, digital, bilateral, sexual, and population differences for subsequent application in the inference of sex. Data were collected from the fingerprints of 172 individuals from the Buenos Aires province and 163 from the Chubut province. RD was assessed for three different count areas for all 10 fingers of each individual. In both sexes and both samples, significant differences among areas were obtained, so that radial-RD>ulnar-RD>proximal-RD. Females presented greater RD than males in all areas and on all fingers. Regarding population differences, no significant differences were found between the Buenos Aires and Chubut samples (except for proximal RD in males). However, both samples showed RD significantly different from that of the Jujuy province. The application of Bayes' theorem allowed for the identification of an RD threshold for discrimination of sexes in these Argentinean samples. In conclusion females consistently exhibit narrower epidermal ridges than males, which may evidence a universal pattern of sexual dimorphism in this trait that can be useful in forensics in the identification of individuals.

Surnames, geographic altitude, and digital dermatoglyphics in a male population from the province of Jujuy (Argentina)

The possible association between finger dermatoglyphic patterns and altitude and surname distribution was analyzed in a sample of adult males from the province of Jujuy, Argentina. We also investigated the biological affinity of this population with other South American natives and admixed populations. Fingerprints were obtained from 996 healthy men, aged 18-20 years, from the highlands (HL: 2500m, Puna and Quebrada) and lowlands (LL: Valle and Selvas). Surnames were classified into native/autochthonous (A) or foreign (F), resulting in three surname classes: FF, when both paternal and maternal surnames were of foreign origin; FA, when one surname was foreign and the other was native; and AA, when both surnames were native. Frequencies of finger dermatoglyphic patterns - arches (A), radial loops (RL), ulnar loops (UL), and whorls (W) - were determined for each digit in relation to geographic location, altitude, and surname origin, resulting in the following categories: HL-FF, HL-FA, HL-AA, LL-FF, LL-FA, and LL-AA. The statistical analyses showed that UL and RL were more common in individuals of HL origin, whereas W and A were more frequent in the LL males (p<0.05). Significant associations were observed between finger dermatoglyphic patterns and surname origin when geographic altitude was considered. In the HL group, UL was associated with AA and FA; in the LL group, the presence of A was associated with FF and FA. The distribution of dermatoglyphic patterns shows that the population of Jujuy belongs to the Andean gene pool and that it has undergone differential levels of admixture related to altitude.

Diversity of human lip prints: a collaborative study of ethnically distinct world populations

BACKGROUND

Cheiloscopy is a comparatively recent counterpart to the long established dactyloscopic studies. Ethnic variability of these lip groove patterns has not yet been explored.

AIM

This study was a collaborative effort aimed at establishing cheiloscopic variations amongst modern human populations from four geographically and culturally far removed nations: India, Saudi Arabia, Spain and Nigeria.

SUBJECTS AND METHODS

Lip prints from a total of 754 subjects were collected and each was divided into four equal quadrants. The patterns were classified into six regular types (A-F), while some patterns which could not be fitted into the regular ones were segregated into G groups (G-0, G-1, G-2). Furthermore, co-dominance of more than one pattern type in a single quadrant forced us to identify the combination (COM, G-COM) patterns.

RESULTS AND CONCLUSION

The remarkable feature noted after compilation of the data included pattern C (a bifurcate/branched prototype extending the entire height of the lip) being a frequent feature of the lips of all the populations studied, save for the Nigerian population in which it was completely absent and which showed a tendency for pattern A (a vertical linear groove) and a significantly higher susceptibility for combination (COM) patterns. Chi-square test and correspondence analysis applied to the frequency of patterns appearing in the defined topographical areas indicated a significant variation for the populations studied.

Sex differences in fingerprint ridge density in the Mataco-Mataguayo population

Ridge density (RD), the number of digital ridges per unit area, varies according to sex, age, and population origin. The main objective of this study was to determine the extent of sexual dimorphism in RD and to set the age at which it appears, in an Amerindian sample from the Mataco-Mataguayo population. The sample studied for this research consisted of 99 males and 110 females, between 6 and 25 years old, which amounts to a total of 2090 fingerprints. Ridge count was carried out on distal radial and distal ulnar and on proximal regions of each finger to explore the RD patterns in order to identify similarities and differences among samples, areas, age groups, and sexes. RD decreased with age and, at all ages, RD was higher on the distal (radial and ulnar) areas, followed by the proximal sides. Females were found to have higher RD than males when older than 12 years, but not when younger. In the radial area, the Mataco-Mataguayo population, in both sexes, presented the RD similar to Spanish samples, but higher than all other populations analysed to date using this method. Variations in RD in the Amerindian population based on sex, age, and topology were confirmed in this work, and it is postulated that these variations are due to developmental differences among individuals and populations. A comparison between the Mataco-Mataguayo and Spanish populations is presented.