Printed artificial sweat as replacement for natural fingermarks: Qualitative and quantitative approach considering an amino acid reagent

The study presented in this paper aims at assessing how printed fingermarks can be used to generate realistic latent marks bearing varying quantities of materials to be detected. Considering dilution series of artificial sweat (eccrine secretion) and 1,2-indanedione/zinc as amino acid reagent, we assessed how printed marks behave in comparison to natural fingermarks provided by a set of 30 donors. The results were assessed in terms of relative intensity (contrast, luminescence) and expert grading (ridge details, overall quality). With regards to the set of 30 donors, this study brought a quantitative look to the influence of intra- and inter-variability on the relative intensity values observed when processing natural fingermarks. This provided new data to further understand the concept of “donorship”. With regards to the use of printed marks, it has been illustrated how dilution series of a concentrated solution allows covering a range of cases: unnatural marks (intensity values well above those obtained with donors), rich marks (corresponding to fingermarks left by good donors), and faint marks (associated with the kind of results observed with poor donors). Such a range of detection performance offers the possibility to generate fine-tuned detection exercises of varying difficulty levels. Printed items made of artificial sweat could hence constitute a valuable alternative to natural secretions in the context of education and proficiency testing.     

Latent Fingermark Aging Patterns (Part I): Minutiae Count as One Indicator of Degradation

The authors are exploring degradation patterns of latent fingermarks over time which can be quantitatively determined in a predictable manner by visual means. Several physical degradation parameters for assessing this hypothesis are evaluated. This article analyzes the parameter “minutiae count” as a function of time. Experiment variables included were secretion type (sebaceous‐rich and eccrine‐rich), substrate (glass and plastic), and exposure to light (dark, shade, and direct light). Depositions were sequentially visualized with Titanium Dioxide powder over a period of 6 months, photographed, and number of minutiae recorded. Results revealed a significant decrease of minutiae for eccrine‐rich marks on glass but insignificant for sebaceous‐rich marks on the same surface. However, significant degradation was observed for both types of secretions on plastic. The authors conclude that the distinctive prevalence of minutiae changes over time indicates with a high degree of certainty the hypothesis is valid and deserves additional exploration.     

Morphology of preimaginal stages of Calliphora vicina Robineau-Desvoidy, 1830 (Diptera, Calliphoridae): a comparative study

A comparative morphological study of preimaginal stages (larvae and pupae) of Calliphora vicina Robineau-Desvoidy, 1830 is presented. The entomological samples came from laboratory colonies bred under controlled environmental conditions (25°C and 60% relative humidity). In this study, a recently published technique to clear Diptera larvae for light microscopy and a standard protocol for scanning electron microscopy were used. For the morphological comparison of larval instars I, II and III, and pupae of C. vicina, different larval regions (cephalic, thoracic and abdominal, including anal division), as well the internal chitinised cephalopharyngeal skeleton, were considered separately. Our results focus on showing the changes observed throughout development for the most important structures in the cephalic region (sensilla of maxillary palpus, antennae and oral ridges), the thoracic region (the first segment and its anterior spinose band) and in the anal division of the abdominal region (posterior spiracles and shape of the papillae). In addition, some morphological structures are described or pictured for the first time, such as the ventral organ and the anterior spiracle of larva I and the antenna sensilla, Keilin's organ and wrinkled area of the anal division of all instars. The cephalopharyngeal skeleton is an important structure for the taxonomy of Diptera larvae in all instars, including Calliphoridae. Our observations in C. vicina indicate that an in-depth review of the sclerite composition is needed. Pupae and larvae stages can only be compared by following the segmentary spinose bands and the anal segment, where the morphology of the posterior spiracles and papillae can be observed, in some cases despite the reduced condition of the latter.     

Development of latent fingermarks on thermal paper: Preliminary investigation into use of iodine fuming

Thermal paper finds its extensive use in the modern day life and could act as a vital piece of physical evidence carrying latent fingermarks. A large number of citations are available in literature suggesting various techniques to develop these marks but all are suffering with one or the other drawbacks such as complex and cumbersome procedure, pre- or post-treatment, background coloration and efficiency to develop aged fingermarks. In present study, a very simple and novel method involving iodine fuming has been suggested to develop fingermarks which were not only permanent but also without any background coloration. The suggested method does not involve any pre- or post-treatment of the substrate and was able to develop very old fingermarks (upto >1 year). In this study an attempt has been made to explain the reaction mechanism of the process. In case of different types of thermal papers, presence of different substituents on leuco dye (lactone ring) structure resulted in development of different colored fingermarks upon reaction with iodine. Sebaceous material laden marks have been found to be more intensely developed as compared to eccrine marks, and the difference was more pronounced in case of aged fingermarks.     

Restoration of engraved marks on steel surfaces by etching technique

It is known that restoration of erased engraved identification marks on the engine and the chassis of a car or on a firearm has low success rate. Unlike stamping, engraving on a metal surface leaves no pronounced, permanent subsurface deformation in the crystalline structure, also called dislocation that can be revealed by suitable methods. Hence, the current research work investigated whether metallographic reagents used in the restoration of stamp (compression) marks could be applied to recover engraved marks on steel surfaces and also to establish the sensitivity and effectiveness of some of these reagents for the restoration of the marks. Experiments were conducted by mechanically engraving alphanumeric characters on several steel plates using a computer controlled engraving machine called Gravograph. The markings were later erased from the above steel plates by removing the metal in stages of 0.01 mm through 0.04 mm below the bottom of the engraving. Several plates were thus prepared wherein each one had been abraded to a specific depth. Then eight metallographic reagents were tested on each one of the above erased plates using a swabbing technique. The results had shown that while most of the reagents were able to restore marks up to certain levels of erasure, the reagent 5 g copper sulphate, 60 ml water, 30 ml concentrated ammonium hydroxide and 60 ml concentrated hydrochloric acid restored marks erased to a depth of 0.04 mm below the engraving depth, thus presenting itself the most sensitive reagent. Quite significantly, the above reagent was also able to decipher successfully the original engraved marks that had been erased and engraved with a new number, or obliterated by centre punching. The results of this research work should benefit the forensic practitioners engaged in the serial number recovery on vehicles, firearms and other objects.     

Recovering obliterated engraved marks on aluminium surfaces by etching technique

A study has been made of the characteristics of restoration of obliterated engraved marks on aluminium surfaces by etching technique. By etching different reagents on 0.61mm thick sheets of aluminium (99wt%) on which some engraved marks had been erased to different depths it was found that the reagent 60% hydrochloric acid and 40% sodium hydroxide on alternate swabbing on the surfaces was found to be the most sensitive one for these metal surfaces. This reagent was able to restore marks in the above plates erased down to 0.04mm below the bottom of the engraving. The marks also presented excellent contrast with the background. This reagent was further experimented with similar aluminium surfaces, but of relatively greater thickness of 1.5mm. It was noticed that the recovery depth increased slightly to 0.06mm; this suggested the dependence of recovery depth on the thickness of the sheet metal. Further, the depth of restoration decreased in cases where the original number was erased and over which a new number was engraved; the latter results are similar to those of steel surfaces reported earlier [M.A.M. Zaili, R. Kuppuswamy, H. Harun, Restoration of engraved marks on steel surfaces by etching technique, Forensic Sci. Int. 171 (2007) 27-32].     

Visualization of Fingermarks Deposits on Untreated Thermal Paper Exploiting the Near Infrared Luminescence

Thermal paper is widely used as a print medium for different applications but it constitutes a tricky substrate for fingermark visualization. An earlier work (J Forensic Sci 2015; 60 :1034) reported how to visualize fingermarks on untreated thermal paper by illuminating the item with a UV-A light source. In the present paper, the potential of the near infrared (NIR) luminescence has been tested on thermal paper compared to the mentioned method. A controlled study was carried out utilizing eccrine enriched fingermarks. The promising outcomes obtained were further confirmed by performing a pseudo-operational trial. Data clearly showed that the use of the NIR filter gave better results. Finally, preliminary tests suggested a different mechanism of reaction induced by fingermarks with respect to the one behind the thermal printing. Thus, NIR luminescence represents a refinement to the suite of optical examination processes, including the potential to increase the number of marks recovered in a noncontact, nondestructive way.     

A survey of some metallographic etching reagents for restoration of obliterated engraved marks on aluminium-silicon alloy surfaces

A brief survey to assess the sensitivity and efficacy of some common etching reagents for revealing obliterated engraved marks on Al-Si alloy surfaces is presented. Experimental observations have recommended use of alternate swabbing of 10% NaOH and 10% HNO(3) on the obliterated surfaces for obtaining the desired results. The NaOH etchant responsible for bringing back the original marks resulted in the deposition of some dark coating that has masked the recovered marks. The coating had been well removed by dissolving it in HNO(3) containing 10-20% acid. However, the above etching procedure was not effective on aluminium (99% purity) and Al-Zn-Mg-Cu alloy surfaces. Also the two reagents (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH suggested earlier for high strength Al-Zn-Mg-Cu alloys [23] were quite ineffective on Al-Si alloys. Thus different aluminium alloys needed different etching treatments for successfully restoring the obliterated marks. Al-Si alloys used in casting find wide applications especially in the manufacture of engine blocks of motor vehicles. Hence, the results presented in this paper are of much relevance in serial number restoration problems involving this alloy.     

Assessing the quality of footwear marks recovered from simulated graves

Footwear marks are one of the most frequently encountered evidence types recovered from a crime scene and can provide valuable scene intelligence regarding potential suspects. It has been acknowledged that impressions of footwear and tools can be recovered from graves, but previous studies have only focused on tool mark recovery. This has led to a lack of published information regarding footwear mark recovery from graves. It is therefore important to demonstrate whether the recovery of footwear marks is feasible and, if so, under what conditions this can be achieved. To address recovery, this study, placed 60 three dimensional (3D) impressions of footwear marks within 60 simulated graves. This was done to assess time (1, 2, 4 months) and at known depths (20, 30, 40 cm). The footwear marks within the graves were covered with clothing or left uncovered. The shoe’s design patterns were grouped and counted in a photographic comparison between the 3D footwear impressions, placed within the test-pits, and any recovered impressions. A grading system was adapted by the authors to score the quality of footwear impressions observed during recovery. The results demonstrate that the preservation and recovery of footwear impressions from graves is feasible. The simulated graves covered with clothing showed better preservation of footwear impressions, but there was no clear evidence that time or depth had an effect. The authors note that careful consideration and vigilant excavation skills are needed when excavating graves which may bear potential footwear marks, as their recovery will lead to an increased amount of intelligence that can link suspects to homicide scenes.     

Morphological findings in fatal drug addiction. An investigation of injection marks, endocrine organs and kidneys

Tissue sections from injection marks from 30 drug addicts and sections from endocrine organs and kidneys from an additional 33 addicts were studied together with endocrine organs and kidneys from 20 'normal' persons. All 83 persons were submitted for medico-legal autopsy at the Institute of Forensic Medicine in Copenhagen. In fresh injection marks haemorrhage in dermis and subcutis was present histologically in all cases. Acute inflammation was present in 38% and acute inflammation together with chronic changes in 41%. Fibrotic thickening of vein wall was seen in 14% and thrombosis in 10%. Birefringent foreign material occurred in 35%. In old injection marks and scars chronic inflammatory changes were observed in 93%, fibrotic thickening of vein wall in 20% and thrombosis in 10% of the cases. Birefringent material occurred in 17%. By comparison of changes in injection marks with the size and histological changes in the corresponding axillary lymph nodes, there was a tendency to a relation between chronic inflammatory changes in old injection marks/scars and enlargement of the lymph nodes in question, but no correlation to the histological degree of immunoactivity. Regarding alterations in the endocrine organs and the kidneys no important differences were demonstrated between drug addicts and 'normal' persons.     

On the sensitivity of some common metallographic reagents to restoring obliterated marks on medium carbon (0.31% C) steel surfaces

Chemical etching, which is the most sensitive method to recover obliterated serial numbers on metal surfaces, has been practised quite successfully in forensic science laboratories all over the world. A large number of etchants suitable for particular metal surfaces based on empirical studies is available in the literature. This article reviews the sensitivity and efficacy of some popular etchants for recovering obliterated marks on medium carbon steel (0.31% C with ferrite–pearlite microstructure) used in automobile parts. The experiments involved engraving these carbon steel plates with some alphanumeric characters using a computer controlled machine “Gravograph” and erasing them to several depths below the bottom of their engraving depth. Seven metallographic reagents of which most of them were copper containing compounds were chosen for etching. The erased plates were etched with every one of these etchants using swabbing method. The results have revealed that Fry’s reagent comprising cupric chloride 90 g, hydrochloric acid 120 mL and water 100 mL provided the necessary contrast and was concluded to be the most sensitive. The same reagent was recommended by earlier workers for revealing strain lines in steel surfaces. Earlier, another reagent containing 5 g copper sulphate, 60 mL water, 30 mL (conc.) ammonium hydroxide, and 60 mL (conc.) hydrochloric acid was proved to be more sensitive to restore erased marks on low carbon steel (0.1% C with ferrite–pearlite structure) [M.A.M. Zaili, R. Kuppuswamy, H. Harun, Restoration of engraved marks on steel surfaces by etching technique, Forensic Sci. Int. 171 (2007) 27–32]. Thus the sensitivity of the etching reagent on steel surfaces appeared to be dependent on the content of carbon in the steel.     

Importance of absolute humidity in the operation of the electrostatic detection apparatus

Data are presented which demonstrate that absolute humidity, not relative humidity, is of primary importance in the development of latent pressure patterns using the Electrostatic Detection Apparatus (ESDA). The data show the importance of document humidification for the optimal development of latent pressure patterns using the ESDA.     

Methods for the enhancement of fingermarks in blood

Fingermarks formed in or by blood often require specific development techniques. This review examines techniques and materials that may be used to enhance and record fingermarks deposited in blood or fingermarks generated by blood-contaminated papillary ridges. A large number of techniques are presented here and are discussed from a chemical as well as practical perspective. It is concluded that an optimized sequence of techniques targeting both latent (non-bloody) and bloody fingermarks must be applied to detect and enhance the maximum number of marks, and therefore optimize the information content from exhibits that may bear marks in blood.     

扫描电镜下缢沟的形态特征

作者用光镜和扫描电镜对縊沟进行对比观察,得出如下结论:(1)扫描电镜下縊沟组织的改变具有较恒定的特征,出血及纤维蛋白检出率远较光镜为高;(2)在光镜下生活反应不明显的生前缢沟,在扫描电镜下其表面及断面均可见红细胞及纤维蛋白形成,并包裹红细胞。縊沟部位胶原纤维之间可见散在大小不等的圆球形脂肪样小滴。缢沟部位肥大细胞的形态改变,有助于生前与死后缢沟的鉴别诊断。     

Evaluation of a Hot Print System for the development of latent fingermarks on thermal paper: A pseudo-operational trial

Enhancement of latent fingermarks on thermal paper poses a number of problems when using traditional methods used for porous substrates due to blackening of the thermal layer as a result of polar solvents present within the reagents and high temperatures oxidising the acid/dye complex. Thus, methods which prevent such reactions are favoured for the development of latent prints on said substrates. A comparative pseudo-operational trial using UV, Hot Print System (HPS), ninhydrin and ThermaNIN was performed on 1000 thermal paper substrates gathered from various sources. The results indicated that the most effective method was an acetone pre-wash followed by ninhydrin. The sequence of HPS-ninhydrin was similarly effective when compared to ninhydrin as a sole technique. ThermaNIN produced fewer marks than ninhydrin but was superior to HPS. Whilst the HPS developed some fingermarks, there was only a very small number of marks uniquely developed by it.     

Examination reports on survived strangulation cases

Clinical-forensic examination of strangulation victims is an increasing part of the routine of many forensic pathology institutes. The cases examined between 2004 and 2008 at the Institute of Legal Medicine of the Hanover Medical School were retrospectively analysed. In total, the study material comprised 218 victims (175 females and 43 males). In 80.7 %, the clinical-forensic examination was performed within 24 hours after the incident. In the overwhelming number of cases, the alleged perpetrator was no stranger. 128 victims (58.7 %) had strangulation marks, 32 victims (14.7 %) ligature marks and 65 victims (29.8 %) nail marks. Four victims showed injuries of the laryngeal and pharyngeal structures (reddening, hematomas, swelling and in one case a fracture of the cricoid cartilage on both sides). Extensive petechiae were predominantly seen in the conjunctivae, the buccal mucosa and the skin of the face in cases where the victims suffered a loss of consciousness. 87 cases (39.9% were classified as potentially life-threatening and 30 cases (13.8 %) as acute life-threatening events. This classification is of legal relevance for the penalty. In addition, 60 victims experienced sexual violence. These results suggest that early clinical-forensic examination is crucial for documenting forensic evidence in support of police investigations and may deliver significant details relevant in court.     

A forensic case study of a naturally mummified brain from the bushveld of South Africa

The present study reports our observations of a naturally mummified human brain found in the bushveld of South Africa. This case extends the geographic and climatic ranges in which mummified brains have been found, and it represents an additional case where no human activity has led to the mummification. The mummified brain was c. one fifth the size of a normal human brain, while the gyral and sulcal patterns of a typical human brain were clear. CT scanning of the brain revealed that subcortical structures, normally evident in this type of imaging, were not discernable, indicating a slow mummification process. Histological examination of the tissue revealed near complete degradation of the microanatomical structure, with only putative Nissl bodies remaining as identifiable neural microstructures. The specimen appears to have survived several veld fires, as well as a high annual rainfall, and a high relative humidity. It is thought that specific conditions amenable to brain mummification, but not other soft tissues, occurred in the skull of this specimen in the weeks postmortem.     

Evaluation of iodine-benzoflavone and ruthenium tetroxide spray reagents for the detection of latent fingermarks at the crime scene

The performance of two spray reagents, iodine-benzoflavone and ruthenium tetroxide (RTX), was evaluated and compared with the conventional technique currently used at the crime scene, that is, powdering. Neither the spray techniques nor powdering were shown to be suitable for all surfaces and ages of marks tested. On some surfaces such as glass and treated wood, powdering was still the superior technique, whereas the spray techniques produced better development on wallpaper, vinyl, and brick. Sequencing work showed that RTX was incompatible with powdering and cyanoacrylate (with a rhodamine 6G stain). Iodine-benzoflavone can be used successfully either before or after powdering in a sequence; however, it was incompatible with cyanoacrylate. Two non-CFC formulations of iodine-benzoflavone using HFC4310mee and HFE7100 solvents were tested and shown not to be as effective as the original Arklone (CFC-113) formulation; however, the HFC4310mee solvent is recommended as the most suitable replacement solvent. Due to the expense of the commercial RTX spray, attempts at formulating a more cost-effective version were also carried out. A formulation was developed that gave comparable development to the commercial version but at a much cheaper cost, and with a shelf life of up to two months. Recommendations are presented for which techniques are suitable for different surfaces and ages of marks. Powdering was shown to be the best technique on all ages of marks tested on treated wood, glass, and also on marks aged three days and older on paint. Iodine-benzoflavone was the best technique on wallpaper, vinyl, brick, and raw wood. RTX was the best detection technique for fresh marks and marks aged up to one day on wallpaper and paint.     

A photometric method for the quantitative mapping of parallel striated marks

A scanning detection system has been developed to provide quantitative surface profile information from cases of parallel striated marks of the type encountered in the forensic laboratory. Details of the scanning system, casting methods and calibration technique are described. Some examples of the results from flat and curved surfaces are presented.     

Nanoscale analysis of the interaction between cyanoacrylate and vacuum metal deposition in the development of latent fingermarks on low-density polyethylene

Vacuum metal deposition (VMD) has been previously demonstrated as an effective development technique for latent fingermarks and in some cases has been shown to enhance prints developed with cyanoacrylate (CA) (superglue) fuming. This work utilizes scanning electron microscopy (SEM) to investigate the interactions of the two development techniques when applied to latent fingermarks on low-density polyethylene. CA is shown to act principally on the eccrine deposits around sweat pores, where polymerization results in long polymer fibrils a few 100 nm in width. Subsequent VMD processing results in additional areas of development, for example, between pores. However, the primary mode of deposition of zinc is by interaction with the polymerized CA, the fibrils of which become decorated with zinc nanoparticles. Areas with limited CA deposition and no significant polymerization are also enhanced with the VMD process, resulting in increased print development.