Cleaning deteriorated elements of ammunition: Development of a procedure applied to cartridge cases from the Second World War.

Deteriorated elements of ammunition can be found while investigating different types of events. Exposure to adverse environmental conditions may lead to metal alteration (corrosion) or organic material deposition (contaminations) on the exposed elements of ammunition. From a forensic perspective, both types of deterioration pose challenges when observing marks left by the firearms used to discharge the corresponding ammunition (e.g. firing pin, extractor). The longer the time of exposure to the adverse environmental conditions, the more challenging the observation of such marks. A literature review highlighted three previously published restorative methods used to clean deteriorated elements of ammunition. The aim of this research is to develop a cleaning procedure applicable to cartridge cases exposed to adverse environmental conditions, while avoiding the degradation of marks left by the firearms used to discharge the corresponding ammunition. A first batch of 21 brass cartridge cases dating back to the Second World War (WWII) was used to develop a cleaning sequence involving the three methods. The efficiency of each restorative method was qualitatively assessed using optical macroscopy and the Evofinder® ballistic identification system. The developed sequence relies on successive applications of Tickopur® TR 7 (a diluted soft metal cleaner), sulfuric acid and finally Aqua Regia (HCl 37% and HNO3 75%), all of them involving ultrasonic baths. The resulting cleaning sequence was subsequently applied to three batches of Second World War cartridge cases discovered in France and Russia. This sequential procedure allows the effective cleaning of WWII brass cartridge cases while highlighting different marks left by firing pins, extractors, ejectors, and breech faces. Applying a forensic analysis and comparison process to the marks highlighted on these elements of ammunition can support the verification of historical facts when reconstructing events which took place more than seventy years ago.

The athletic characteristics of Olympic sports to assist anti-doping strategies.

The determinants of success in Olympic Games competition are specific to the athletic demands of the sporting event. A global evaluation to quantify the athletic demands across the spectrum of the Olympic Games sport events has not previously been conducted. Thus far, the interpretation and the comparison of sport physiological characteristics within anti-doping organisations (ADOs) risk assessments remains subjective without a standardised framework. Despite its subjective assessment, this information is a key component of any anti-doping programme. Sport characteristics inevitably influence the type of substances and/or methods used for doping purposes and should be captured through a comprehensive analysis. Seven applied sport scientists independently conducted an assessment to quantify the athletic demands across six preselected athletic variables. A principal component analysis was performed on the results of the panel's quantitative assessment for 160 Olympic sport events. Sport events were clustered using the Hierarchical Density Based Spatial Clustering of Applications with Noise (HDBSCAN) algorithm. The HDBSCAN identified 19 independent cluster groups; 36 sport events remained statistically unassigned to a cluster group representing unique and event-specific athletic demands. This investigation provides guidance to the anti-doping community to assist in the development of the sport specific physiology component of the risk assessment for Olympic Games disciplines. The dominant athletic characteristics to excel in each of these individual events will highlight areas of how athletes may strive to gain a competitive advantage through doping strategies, and inform the development of an effective and proportionate allocation of testing resources.

Influence of the printing process on the traces produced by the discharge of 3D-printed Liberators.

Since its introduction in 1986, 3D printing technology is in constant development. 3D printers are becoming more and more performant and accessible. In 2013, the Liberator blueprints are released online. This single-shot pistol can be entirely manufactured using a 3D printer, except for the firing pin and the ammunition. First, this research aims at establishing an overview of all the elements and traces potentially present when a 3D-printed firearm is involved, whether it is fired or not. In the second part, we study these elements for exploitability to obtain information about the manufacture of the firearm (printing processes, 3D printers and polymers). For this purpose, a total of 36 Liberators were manufactured using different printing conditions (i.e., printing processes, printers, polymers and parameters). The tested printing processes were based on the principles of Material Extrusion (ME), Vat Photopolymerization (VP) and Powder Bed Fusion (PBF). All 3D-printed firearms manufactured via ME and PBF were able to fire whereas Liberators manufactured by VP printing could not be fired. This could be explained by the lack of precision of the prints making it impossible to assemble some of the Liberators, or by the fact that the polymer was not suitable to produce the springs. All the barrels were broken by the discharge, projecting polymer pieces or fragments into the environment. These polymer pieces or fragments were examined to determine which printing process was used as well as other elements related to printing parameters and conditions (e.g., layer height, filling pattern and infill density). This information is useful to determine whether a certain command file, slicer or 3D printer could be at the source of a questioned 3D-printed firearm. Melted polymer or polymer particles on elements of ammunition may also be present after the firing process. However, the examination of these particles does not allow inferring other information, except the possible use of a 3D-printed polymer firearm.

Analysis of Google Trends to monitor new psychoactive substance. Is there an added value?

The past decade has seen an increase in the development and availability of a broad category of drugs, known as new psychoactive substances (NPS). NPS are challenging for public health authorities, therefore the two major drug monitoring bodies - the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) and the United Nations Office on Drugs and Crime (UNODC) - have implemented the EU Early Warning System (EWS) and Early Warning Advisory (EWA), respectively. While these monitoring systems are informative, it is difficult to keep up with the constant and rapid developmental rate of NPS. The EMCDDA has recognised the need for an alternative and technologically derived early warning system. The aim of this research is to determine whether Google Trends and drug discussion forum data can be used to complement early warning systems for NPS. Forty-eight substances were used in this study and classed into groups based on their chemical structure, following the UNODC classification system. Google Trends data (time range: 2004-2019) and drug forum data (time range: 2003-2018) were extracted for each substance and visual trend profiles were created for class groups as well as individual substances. Analysis was conducted to determine when a substance first appeared on Google Trends and a drug discussion forum as well as their trends over time. This date of first appearance was then compared to the date the substance was first reported to UNODC. Of the three data sources utilised, substances were most likely to appear on Google Trends first. Amongst the different classes of NPS, discernible trends ('block', 'successive', and 'generational' trends) were observed. These trends reflect the evolution of the manufacture of substances or generations of substances that has been observed in the literature. For example, in the synthetic cannabinoids' category, a generational trend is observed that corresponds to the different generations of synthetic cannabinoids. When comparing Google Trends and Drugs-Forum directly, the order of appearance and duration of presence for substances aligns accurately for most classes. Google Trends showed the emergence, persistence, or transient nature of substances, which could direct the focus of law enforcement, health organisation and laboratory resources towards a limited number of substances. When one considers the reliance of individual information seeking on the Web as well as the prominence of NPS on the Web, it becomes clear that Google Trends and drug discussion forums could be used as a complement to current early warning systems.

Monitoring new psychoactive substances: Exploring the contribution of an online discussion forum.

BACKGROUND: The rapid emergence of new psychoactive substances (NPS) is a challenge for public health authorities and law enforcement. The phenomenon is strengthened since the increase of the Internet usage. Not only used to trade NPS, the Web is an important source of information for both potential drug consumers and experienced users. Discussion forums are among these sources of information. They are meeting points for different groups of users and include a wide range of trip reports, questions and consumption tips. Since the discussions are archived over a long period, they can be used to monitor the interest of consumers for particular substances over time. This research aims at understanding the contribution of data extracted from a major online discussion forum within a systematic monitoring process. METHOD: Data were collected from a discussion forum (i.e. Drugs-forum). Within the sections of the forum, the titles, content of discussion, number of replies, and the date of the first discussion were crawled and stored in a dedicated database. The intensity of the discussions related to 42 substances considered as NPS was measured through an indicator allowing to assess the popularity of substances. Furthermore, the appearance of 15 substances on the forum was compared to the date of formal notification to the EU early warning system. RESULTS: An evolution of the different classes of substances, as well as an evolution of specific substances within a class were highlighted. Some substances were discussed for a long period of time (e.g. Kratom, 25i-NBOMe, MDPV) while others were discussed very briefly (e.g. 5-MeO-DPT, NM-2AI). Out of the fifteen substances subjected to a risk assessment from the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), nine of them appeared on the forum before or at the same time as their first date of notification to the EU early warning system. CONCLUSION: In line with previous research on doping products, this article shows the potential of the monitoring of online forums in the context of psychoactive substances. Besides, the system designed to collect the data is flexible and can be systematically updated to fuel a monitoring process. It informs not only on the presence/absence of a substance in discussions between consumers, but also on its evolution over time. Such results could benefit academic research and organizations studying the NPS phenomenon. Precisely, it could complement existing early warning systems and benefit law enforcement agencies and policy makers.

How to recognise the traces left on a crime scene by a 3D-printed Liberator? Part 2. Elements of ammunition, marks on the weapons and polymer fragments.

The Liberator is a firearm that can be manufactured from its blueprints by the means of a 3D-printer. This handgun is composed of nineteen pieces: eighteen made of printed polymer and one metallic nail. This study focuses on the physical traces which can be found and exploited from a forensic point of view after the discharging of such types of pistols. Two main aspects have been investigated: (1) whether it can be inferred that a 3D-printed handgun was used when investigating a scene; (2) when presuming the use of a 3D-printed Liberator on a scene. Six Liberators were manufactured, assembled and discharged. The discharge occurred under controlled conditions to allow the collection of ballistics data and traces produced by the shooting. Elements of ammunition - cartridge cases and projectiles - that were fired during an experimental campaign appeared to carry polymeric materials (flakes, melted polymer or both). Besides, we observed that the fired ammunition elements lacked traditional marks left by the metal pieces of a conventional firearm. Indeed, the projectiles did not carry rifling marks and the cartridge cases were found torn or swollen. Fragments or larger pieces of polymer were found, mostly on the ground, near the location of the discharge, up to nine metres away. The impression of the cartridge case head stamp was also found on a part of the Liberator called the "hammer body". This study showed that the discharge of a 3D-printed Liberator is expected to produce traces that can be transferred onto and recovered from the printed firearm, the cartridge case, the projectile, the target, and the environment of the discharge. These traces are different from those left by conventional firearms. When found on investigation scenes, some of these traces can inform on the use of a 3D-printed handgun and contribute to the reconstruction of a shooting event involving such a weapon. This study suggests that the approach adopted when investigating a scene must be adapted in terms of traceology when the use of such firearm is suspected.

Secondary transfer of organic gunshot residues: Empirical data to assist the evaluation of three scenarios.

The present study aimed at providing data to assess the secondary transfer of organic gunshot residues (OGSR). Three scenarios were evaluated in controlled conditions, namely displacing a firearm from point A to point B, a simple handshake and an arrest involving handcuffing on the ground. Specimens were collected from the firearm, the hands of the shooter and the non-shooter undergoing the secondary transfer in order to compare the amounts detected. Secondary transfer was observed for the three scenarios, but to a different extent. It was found that displacing a firearm resulted in secondary transfer in <50% of the experiments. The firearm also had an influence, as contrary to the pistol, no secondary OGSR were detected using the revolver. Shaking the hand of the shooter also transferred OGSR to the non-shooter's hand. In that case, the amount of OGSR was generally higher on the shooter than on the non-shooter. Finally, the largest secondary transfer was observed after the arrest with handcuffing with positive results in all cases using the pistol. In that scenario, the amounts on the shooter and the non-shooter were in the same range. This study highlights that the secondary transfer must be taken into account in the interpretation of OGSR. Indeed, an individual's hands might be contaminated by handling a firearm or having physical contact with a shooter.

Comparison of three bullet recovery systems.

Comparing the marks left on questioned bullets to those left on reference bullets is the main aim of a firearm identification expertise. Thus, producing reference bullets with a questioned firearm is an essential step. Different kinds of system have been developed to safely recover bullets fired from questioned firearms. However, the performance of each system and its impact on traces left on the bullets have not been addressed. Three bullet recovery systems - a horizontal water tank, a cotton tube and a recently designed fleece - were used to fire seven types of ammunition of various type, shape and casing. The bullets were then described and images of their surface were acquired with an automatic system to study the impact of each system on the bullets. The water tank is the more efficient system in terms of quality of the marks. However, it cannot be used to fire every type of ammunition. Some of them, such those used by law enforcement, tend to be damaged with this system. A way to mitigate the problem is to use the cotton or the fleece-based systems, the latter being more universal. It requires a cleaning step to remove all the fibres from the surface of the bullet, but the marks left by the weapon are still of interest.

How to recognize the traces left on a crime scene by a 3D-printed Liberator?: Part 1. Discharge, exterior ballistic and wounding potential.

The Liberator is a firearm that can be manufactured from its blueprints, using a 3D-printer. This weapon made of nineteen pieces - eighteen in printed plastic and one metallic nail - raises questions such as its ability to fire a round, its wounding potential and the traces produced by its discharge. In particular, knowledge must be gained to infer that a 3D-printed handgun was used, reconstruct the shooting event involving such handgun, and gather information related to the type of 3D-printed handgun used. This study focused on the traces that could orientate forensic investigations when the use of a 3D-printed Liberator is suspected. In a first step, the Liberator was investigated to study its behaviour during the discharge and characterize traces produced by the discharge. To fulfil this goal, some Liberators were printed and assembled. Six Liberators fired a round. The discharge of the weapons was done under specific conditions allowing to collect ballistics data and traces produced by the shooting. The results showed that the barrel tended to break between the ignition of the primer and the moment the projectile exited the muzzle. The speed of the projectiles reached 140m/s when the barrel broke, while it was about 170m/s when barrel remained intact. The trajectory of the projectiles was sometimes disrupted, and the projectile tumbled on itself. It was thus very difficult to characterize the trajectory. The cavity wound caused by the fastest bullet was typical of a handgun wound firing a FMJ projectile (penetration of 21cm in ballistics soap). On the other hand, the cavity caused by the slowest bullet was more representative of a splinter wound (penetration of 14cm in ballistics soap). The study of gunshot residues collected on adhesive targets showed the presence of unburnt particles and small perforations caused by polymer pieces that concentrated around the entry holes.

Characterising the online weapons trafficking on cryptomarkets.

Weapons related webpages from nine cryptomarkets were manually duplicated in February 2016. Information about the listings (i.e. sales proposals) and vendors' profiles were extracted to draw an overview of the actual online trafficking of weapons. Relationships between vendors were also inferred through the analysis of online digital traces and content similarities. Weapons trafficking is mainly concentrated on two major cryptomarkets. Besides, it accounts for a very small proportion of the illicit trafficking on cryptomarkets compared to the illicit drugs trafficking. Among all weapon related listings (n=386), firearms only account for approximately 25% of sales proposal since the proportion of non-lethal and melee weapons is important (around 46%). Based on the recorded pseudonyms, a total of 96 vendor profiles were highlighted. Some pseudonyms were encountered on several cryptomarkets, suggesting that some vendors may manage accounts on different markets. This hypothesis was strengthened by comparing pseudonyms to online traces such as PGP keys, images and profiles descriptions. Such a method allowed to estimate more accurately the number of vendors offering weapons across cryptomarkets. Finally, according to the gathered data, the extent of the weapons trafficking on the cryptomarkets appear to be limited compared to other illicit goods.

A geographical analysis of trafficking on a popular darknet market.

Cryptomarkets are online marketplaces, located on the darknet, that facilitate the trading of a variety of illegal goods, mostly drugs. While the literature essentially focus on drugs, various other goods and products related to financial or identity fraud, firearms, counterfeit goods, as well as doping products are also offered on these marketplaces. Through the analysis of relevant data collected on a popular marketplace in 2014-2015, Evolution, this research provides an analysis of the structure of trafficking (types and proportions of products, number of vendors and shipping countries). It also aims at highlighting geographical patterns in the trafficking of these products (e.g. trafficking flows, specialisation of vendors and assessment of their role in the distribution chain). The analysis of the flow of goods between countries emphasises the role of specific countries in the international and domestic trafficking, potentially informing law enforcement agencies to target domestic mails or international posts from specific countries. The research also highlights the large proportion of licit and illicit drug listings and vendors on Evolution, followed by various fraud issues (in particular, financial fraud), the sharing of knowledge (tutorials) and finally goods, currencies and precious metals (principally luxury goods). Looking at the shipping country, there seems to be a clear division between digital and physical products, with more specific information for physical goods. This reveals that the spatial analysis of trafficking is particularly meaningful in the case of physical products (such as illicit drugs) and to a lesser extent for digital products. Finally, the geographical analysis reveals that spatial patterns on Evolution tend to reflect the structure of the traditional illicit market. However, regarding illicit drugs, country-specificity has been observed and are presented in this article.

Buying drugs on a Darknet market: A better deal? Studying the online illicit drug market through the analysis of digital, physical and chemical data.

Darknet markets, also known as cryptomarkets, are websites located on the Darknet and designed to allow the trafficking of illicit products, mainly drugs. This study aims at presenting the added value of combining digital, chemical and physical information to reconstruct sellers' activities. In particular, this research focuses on Evolution, one of the most popular cryptomarkets active from January 2014 to March 2015. Evolution source code files were analysed using Python scripts based on regular expressions to extract information about listings (i.e., sales proposals) and sellers. The results revealed more than 48,000 listings and around 2700 vendors claiming to send illicit drug products from 70 countries. The most frequent categories of illicit drugs offered by vendors were cannabis-related products (around 25%) followed by ecstasy (MDA, MDMA) and stimulants (cocaine, speed). The cryptomarket was then especially studied from a Swiss point of view. Illicit drugs were purchased from three sellers located in Switzerland. The purchases were carried out to confront digital information (e.g., the type of drug, the purity, the shipping country and the concealment methods mentioned on listings) with the physical analysis of the shipment packaging and the chemical analysis of the received product (purity, cutting agents, chemical profile based on minor and major alkaloids, chemical class). The results show that digital information, such as concealment methods and shipping country, seems accurate. But the illicit drugs purity is found to be different from the information indicated on their respective listings. Moreover, chemical profiling highlighted links between cocaine sold online and specimens seized in Western Switzerland. This study highlights that (1) the forensic analysis of the received products allows the evaluation of the accuracy of digital data collected on the website, and (2) the information from digital and physical/chemical traces are complementary to evaluate the practices of the online selling of illicit drugs on cryptomarkets.