Changes in Fingerprints Depending on Physiological Factors

The aim of the study was to determine the effect of gender, body mass index, and time on the width of friction ridge impressions in fingerprints and the content of sweat and sebum forming the print. The research showed that the friction ridge impressions of women are significantly wider than those of men, and this tendency persists throughout the existence of the print. The differences may result from the anatomical structure of the skin, as well as from the use of protective products such as creams, which are used more often by women. The width of friction ridge impression is similar in underweight and overweight people, but greater than in those with normal body weight, and the amount of sweat and sebum increases with body weight. The passage of time significantly reduces both the width of the friction ridge impression and the content of sweat and sebum secretions in the print.     

Revisiting the Thermal Development of Latent Fingerprints on Porous Surfaces: New Aspects and Refinements*

Abstract: Although the ability to develop latent fingerprints on paper using heat alone has been noted previously, it has been considered impractical for casework and inferior to other techniques. Here a new refinement of the technique is demonstrated for the high quality development of latent fingerprints on porous surfaces such as paper. Fingerprints deposited on various papers were developed by exposing them to hot air with a temperature in the vicinity of 300°C, for periods of c. 10–20 sec. Several different heating methods were tested. The novel observation was made that after shorter heating times, fluorescent prints could be observed. These became visible after longer heating times, as noted by earlier workers, but with greatly improved contrast compared with their results. Prints from various donors (and aged prints) were developed with excellent ridge contrast. Direct heating methods (such as with a hot plate or press) produced inferior results. The refined technique, which is simple, safe and inexpensive compared with conventional methods, has great potential for use in forensic laboratories.     

Microwave Selective Thermal Development of Latent Fingerprints on Porous Surfaces: Potentialities of the Method and Preliminary Experimental Results

The thermal development of latent fingerprints on paper surfaces is a simple, safe, and chemicals‐free method, based on the faster heating of the substrate underlying the print residue. Microwave heating is proposed for the first time for the development of latent fingerprints on cellulose‐based substrate, in order to add to the thermal development mechanism the further characteristic of being able to heat the fingerprint residues to a different extent with respect to the substrate, due to the intrinsic difference in their dielectric properties. Numerical simulation was performed to confirm and highlight the selectivity of microwaves, and preliminary experimental results point out the great potentialities of this technique, which allowed developing both latent sebaceous‐rich and latent eccrine‐rich fingerprints on different porous surfaces, in less than 30 sec time with an applied output power of 500 W. Microwaves demonstrated more effectiveness in the development of eccrine‐rich residues, aged up to 12 weeks.     

Recovery of Latent Fingerprints and DNA on Human Skin*

Abstract: The project “Latent Fingerprints and DNA on Human Skin” was the first systematic research in Europe dealing with detection of fingerprints and DNA left by offenders on the skin of corpses. One thousand samples gave results that allow general statements on the materials and methods used. The tests were carried out according to a uniform trial structure. Fingerprints were deposited by natural donors on corpses. The latent fingerprints were treated with magnetic powder or black fingerprint powder. Afterward, they were lifted with silicone casting material (Isomark^®) or gelatine foil. All lifts were swabbed to recover DNA. It was possible to visualize comparable and identifiable fingerprints on the skin of corpses (16%). In the same categories, magnetic powder (18.4%) yielded better results than black fingerprint powder (13.6%). The number of comparable and identifiable fingerprints decreased on the lifts (12.7%). Isomark^® (14.9%) was the better lifting material in comparison with gelatine foil (10.1%). In one‐third of the samples, DNA could be extracted from the powdered and lifted latents. Black fingerprint powder delivered the better result with a rate of 2.2% for full DNA profiles and profiles useful for exclusion in comparison with 1.8% for the magnetic powder traces. Isomark^® (3.1%) yielded better results than gelatine foil (0.6%).     

An Investigation into the Effects of Force Applied During Deposition on Latent Fingermarks and Inked Fingerprints Using a Variable Force Fingerprint Sampler

Physical factors, including the magnitude of the force applied during fingermark deposition, may affect friction ridge surface area and clarity, and the quantity of residue transferred. Consistency between fingermarks may be required; for example, in research projects, yet differences between marks are likely to exist when physical factors are not controlled. Inked fingerprints and latent fingermarks were deposited at 1–10 N at 1 N increments using a variable force fingerprint sampler to control the force, angle of friction ridge and surface contact, and the duration of friction ridge and surface contact. Statistically significant differences existed between the length and width measurements of the inked prints (p ≤ 0.05), particularly at lower forces. Scanning electron microscopy and surface plot analysis demonstrated how differences in force applied during deposition affected ridge surface area, displacement of latent residue, and differences in the quantity of residue transferred. Consistency between inked prints was demonstrated at equivalent forces.     

LCMS Analysis of Fingerprints,the Amino Acid Profile of 20 Donors

The analysis of amino acids present in fingerprints has been studied several times. In this paper, we report a method for the analysis of amino acids using an fluorenylmethyloxycarbonyl chloride‐derivatization for LC separation and MS detection. We have obtained good results with regard to the calibration curves and the limit of detection and LOQ for the target compounds. The extraction of the amino acids from the substrates used proved to be very efficient. Analysis of the derivatized amino acids enabled us to obtain full amino acid profiles for 20 donors. The intervariability is as expected rather large, with serine as the most abundant constituent, and when examining the total profile of the amino acids per donor, a characteristic pattern can be observed. Some amino acids were not detected in some donors, or fell out of the range of the calibration curve, where others showed a surprisingly high amount of material in the deposition analyses. Further investigations will have to address the intravariability of the amino acid profiles of the fingerprints from donors. By the development of the analytical method and the application to the analysis of fingerprints, we were able to gain insight in the variability of the constituents of fingerprints between the donors.     

The Effect of Time and Temperature on the Persistence and Quality of Latent Fingerprints Recovered from 60-Watt Incandescent Light Bulbs

To understand how time and temperature could affect latent fingerprints, wooden pallets were used to construct five units that each housed ten 60-watt incandescent light bulbs. Fingerprints were deposited on the top, middle, and base of the globes. The bulbs were powered on (except the control bulb in each unit) for 18, 48, 72, 120, 168, 336, 504, and 672 h. Fingerprints recovered from the bulbs by tape lift after black powder processing were given a quality score. A thermal imaging camera determined temperatures on three areas of the bulbs. Fingerprints on the top of the globe (156.3°C) had the lowest quality score, and fingerprints on the middle of the globe (112.6°C) had the highest quality score. The mean quality scores of the three temperature classes were within one standard deviation of one another, meaning there is no way to estimate fingerprint age based on its quality after heat exposure.     

Effect of Aging and Surface Interactions on the Diffusion of Endogenous Compounds in Latent Fingerprints Studied by Mass Spectrometry Imaging,

The ability to determine the age of fingerprints would be immeasurably beneficial in criminal investigations. We explore the possibility of determining the age of fingerprints by analyzing various compounds as they diffuse from the ridges to the valleys of fingerprints using matrix‐assisted laser desorption/ionization mass spectrometry imaging. The diffusion of two classes of endogenous fingerprint compounds, fatty acids and triacylglycerols (TGs), was studied in fresh and aged fingerprints on four surfaces. We expected higher molecular weight TGs would diffuse slower than fatty acids and allow us to determine the age of older fingerprints. However, we found interactions between endogenous compounds and the surface have a much stronger impact on diffusion than molecular weight. For example, diffusion of TGs is faster on hydrophilic plain glass or partially hydrophilic stainless steel surfaces, than on a hydrophobic Rain‐x treated surface. This result further complicates utilizing a diffusion model to age fingerprints.     

The Effects of Interviewer Gender and Child Gender on the Informativeness of Alleged Child Sexual Abuse Victims in Forensic Interviews

Most students of forensic interviews have focused on the interrogatory techniques used to elicit information from alleged child abuse victims. We asked how the gender of the interviewer and the gender of the child affected this process. Forensic investigators in three countries used either the NICHD structured interview protocol or local standard interview practices to interview 672 alleged victims who ranged in age from 4 to 14 years. Analyses of the interviews showed significant effects of gender on both the interviewers' behavior and the amount of information provided by children. Female interviewers asked boys more invitations, as well as absolutely and proportionally more suggestive questions, than they did girls, whereas male interviewers interviewed boys and girls similarly. Children's responses varied depending on their gender and age, the gender of the interviewer, and the type of question asked. Girls of all ages provided more information in response to directive questions posed by female rather than male interviewers whereas boys did not respond differently to male and female interviewers. The oldest girls provided more information in response to option-posing questions posed by male interviewers. More information was provided by the younger children in response to suggestive prompts from interviewers of the opposite gender. The gender-of-interviewer effects were attenuated in protocol-guided interviews.     

An Optimized DNA Analysis Workflow for the Sampling,Extraction, and Concentration of DNA obtained from Archived Latent Fingerprints

DNA profiles have been obtained from fingerprints, but there is limited knowledge regarding DNA analysis from archived latent fingerprints—touch DNA “sandwiched” between adhesive and paper. Thus, this study sought to comparatively analyze a variety of collection and analytical methods in an effort to seek an optimized workflow for this specific sample type. Untreated and treated archived latent fingerprints were utilized to compare different biological sampling techniques, swab diluents, DNA extraction systems, DNA concentration practices, and post‐amplification purification methods. Archived latent fingerprints disassembled and sampled via direct cutting, followed by DNA extracted using the QIAamp® DNA Investigator Kit, and concentration with Centri‐Sep? columns increased the odds of obtaining an STR profile. Using the recommended DNA workflow, 9 of the 10 samples provided STR profiles, which included 7–100% of the expected STR alleles and two full profiles. Thus, with carefully selected procedures, archived latent fingerprints can be a viable DNA source for criminal investigations including cold/postconviction cases.     

Viability of Human Articular Chondrocytes Harvested Postmortem: Changes with Time and Temperature of In Vitro Culture Conditions

Different studies of long‐term chondrocytes viability have shown a gradual reduction as a function of time and ambient temperature. The aim of our in vitro study was to establish chondrocyte postmortem viability curves for 4°C, 11°C, 23°C, 35°C during 63 days after the donors' death. Osteochondral cylinders were procured from the knees of 16 male donors (20–47 years), stored in preservation media that was not changed, and analyzed in 3‐day intervals using a confocal laser scanning microscope. A significant influence of time on viability was found from Day 9 (p = 0.0029) and onwards (p < 0.0001). The lowest overall chondrocyte viability was at 35°C, followed by 4°C (p < 0.0001). The conditions used in this in vitro analysis suggest that similar viabilities may occur while in situ in the decedent. Further studies of chondrocyte viability from individuals with known postmortem intervals may show premise to help evaluate time since death in the late postmortem interval.     

The Effect of Temperature and Laboratory Rearing Conditions on the Development of Dermestes maculatus (Coleoptera: Dermestidae)

Experiments were conducted to study the life cycle of Dermestes maculatus and to establish the total developmental time and the developmental time of immature stages, in relation with six different temperatures. We also analyzed the variations in size, morphology, and other indicators of temporal variation during life cycle of D. maculatus, in relation with temperature. One hundred larvae were selected per experiment, reared individually. The remaining larvae were reared to evaluate and establish temporal variations among the instars (length, cephalic width, and dry weight). In all trials, survivorship was greater than 50% and seven larval instars were found. Data of the average developmental time of immature stages and of the total cycle, at different temperatures, are provided. This is of relevance when estimating particularly, a minimum PMI. No relation between morphometric parameters and temperature was found, suggesting that other random factors may have been involved. Thus, this indicates that the method of isomegalen diagrams could not be used for calculating PMI.     

Detection and Identification of Explosive Particles in Fingerprints Using Attenuated Total Reflection-Fourier Transform Infrared Spectromicroscopy

Abstract:  The application of attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectromicroscopy for detection of explosive particles in fingerprints is described. The combined functions of ATR-FTIR spectromicroscopy are visual searching of particles in fingerprints and measuring the FTIR spectra of the particles. These functions make it possible to directly identify whether a suspect has handled explosives from the fingerprints alone. Particles in explosive contaminated fingerprints are either ingredients of the explosives, finger residues, or other foreign materials. These cannot normally be discriminated by their morphology alone. ATR-FTIR spectra can provide both particle morphology and composition. Fingerprints analyzed by ATR-FTIR can be used for further analysis and identification because of its non-destructive character. Fingerprints contaminated with three different types of explosives, or potential explosives, have been analyzed herein. An infrared spectral library was searched in order to identify the explosive residues. The acquired spectra are compared to those of finger residue alone, in order to differentiate such residue from explosive residue.     

The effects of deprivation on the time spent examining crime scenes and the recovery of DNA and fingerprints

DNA and fingerprint identifications are now accepted as an integral part of the investigation of a wide range of criminal offences from burglary and auto crime to serious and major crime. Despite this, there is still much variation between U.K. police forces in the recovery of fingerprint and DNA material from crime scenes. Analysis of burglary and auto crime data for Northamptonshire, U.K., during a 3-year period has enabled an examination of the relationship between the deprivation of the neighborhood in which the crime was committed and the level of service provided by Crime Scene Examiners. The results indicate that the time spent examining a crime scene for forensic evidence is not affected by the deprivation of the neighborhood. Further, there is no statistical significance between deprivation and the recovery of fingerprints from the crime scene. The relationship between deprivation and DNA recovery is, however, statistically significant with DNA being recovered more frequently from less deprived neighborhoods.     

Methods of Choice in Completed Suicides: Gender Differences and Review of Literature

Abstract:  Suicide is an important public health hazard worldwide. A 4-year retrospective study from January 2000 to December 2003 was conducted to identify the favored methods in realized suicides among males and females in the west coastal region of India. During the study period, a total of 539 cases of suicidal deaths were autopsied. Males were predominantly affected (male: female—1.9:1). The age of the victims ranged from 13 to 90 years in males (mean = 40.1 years, median = 37.0 years) and 15 to 85 years in females (mean = 36.6 years, median = 32.0 years). Most favored method of suicide amongst males and females was hanging (36.9%, n  = 199) followed by poisoning (34.7%, n  = 187). Male dominance was apparent for each method of suicide except for self-immolation. Males were relatively more likely to use hanging and poisoning while females were more likely to prefer drowning and self-immolation as methods of suicide. Relatively younger females (mean   = 33.0 years, median = 32.0 years) preferred hanging as a method of suicide when compared to males (mean = 42.4 years, median = 40.0 years). Among females, significantly younger females resorted to hanging when compared to older females who preferred drowning. On investigating the various theories proposed for choice of suicide methods in males and females in different regions we conclude that preference of method of suicide in men and women is complexly determined. In this region, availability, accessibility, popularity, and socioacceptability seem to be the major determinants in the choice of methods among males and females rather than violence associated and lethality of the method. Females were as likely to use lethal and violent methods as males in this region.     

Carbon‐Based Fingerprint Powder as a One‐Step Development and Matrix Application for High‐Resolution Mass Spectrometry Imaging of Latent Fingerprints

Carbon‐based materials are often used as matrices for matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) and its imaging (MALDI‐MSI). However, researchers have refrained from using carbon‐based fingerprint powder (CFP) as a matrix due to high background and contamination. In this work, the compatibility of CFP is reevaluated with MALDI‐MSI using a high‐resolution mass spectrometer (HRMS) and compared to traditional organic matrices. Relevant fingerprint compounds were easily distinguished from carbon cluster peaks when using HRMS. For fair comparison, half of a fingerprint was dusted with CFP while the other half was dusted with traditional organic matrices. All compounds studied had comparable, or higher, signal‐to‐noise (S/N) ratios when CFP was used as the matrix. Additionally, chemical image qualities closely followed the trend of S/N ratios. CFP proved to be an effective one‐step development and matrix application technique for MALDI‐MSI of latent fingerprints, when carbon cluster peaks are well separated by a HRMS.     

Fluorescence of 1,2‐Indanedione with Amino Acids Present in the Fingerprint Residue: Application in Gender Determination

1,2‐indanedione is used for latent fingerprint visualization on porous surfaces. In this paper, fluorescence spectra of 1,2‐indanedione after reacting with 21 individual amino acids present in latent fingerprints residue were measured in water‐methanol solutions. The fluorescence intensity depends on the amino acid used, while the fluorescence peak does not change much. The concentration of amino acids in fingerprint residue in females is almost the double of their concentration in males. This property combined with fluorescence of 1,2‐indanedione‐amino acids compounds is used for gender determination, by comparing the fluorescence intensity peaks in the same experimental conditions. In this preliminary study, the fluorescence signal from the samples representing females was almost two times the signal for samples representing males. In addition to the reduction by almost 50% of the number of suspects in a criminal research case, these results could be helpful in gaining some knowledge about the papillary residue composition.     

Accuracy of Three Age Estimation Methods in Children by Measurements of Developing Teeth and Carpals and Epiphyses of the Ulna and Radius

Abstract: The aim of this study was to compare the accuracy of three methods for age estimation in children: the measurements of open apices in tooth roots (T), the ratio between the total area of carpal bones and epiphyses of the ulna and radius (HW), and the combined method (THW). The sample consisted of 288 Caucasian Italian children (152 boys and 136 girls) aged between 5 and 15 years. Accuracy was determined as the difference between estimated age and chronological age, and accuracy was assessed by analyzing individuals’ orthopantomograms and hand‐wrist radiographs. Accuracies were 0.41 years for girls and 0.54 years for boys with the THW method; for the HW method, 1.00 years for girls and 0.92 years for boys; and for the T method, 0.62 years for girls and 0.71 years for boys. THW is the most accurate technique for age estimation in these children.     

The Effects of Differential Extraction Conditions on the Premature Lysis of Spermatozoa,

The purpose of this study was to determine the effect Proteinase K, sodium dodecyl sulfate (SDS), incubation times, and temperatures had on differential extraction efficiencies and the premature lysis of spermatozoa. The effect was measured using Quantifiler^® Duo and Identifiler? PCR Amplification kits, where the resultant male and female DNA concentrations and their ratios within the nonsperm‐ and sperm fractions (SFs) were determined. Comparisons between expected and observed ratios illustrate the quantity of female DNA in the SF increased when Proteinase K was absent during the initial incubation. Additionally, there is no indication of simultaneous sperm and epithelial cell lysis in the absence of DTT at Proteinase K concentrations ranging from 10 to 300 μg/mL. All other conditions exhibited minimal variation in DNA concentration. Therefore, despite the various protocols used for the differential lysis of cell mixtures encountered in casework, the method is robust and successful at most conditions.     

美国法庭科学证据的应用与发展

＂法庭科学＂萌芽于古代中国,兴盛于近现代西方国家,最终发展成为具备完整科学体系的现代意义上的法庭科学学科。法庭科学证据的应用与发展显然与法庭科学的发展与应用密切相关,它们相互制约,相互促进。美国司法制度中关于法庭科学证据的证明力、可信度、可采性的分立质疑对法庭科学本身的发展无疑起到鞭策与促进作用。美国法庭科学证据的司法制度以及常用的一些传统与高技术法庭科学证据的使用过程中存在的许多问题,理解法庭科学证据标准,对我国法庭科学及其证据的研究与应用有所启迪。