Forensic Microbiology: When, Where and How.

Forensic microbiology is a relatively new discipline, born in part thanks to the development of advanced methodologies for the detection, identification and characterization of microorganisms, and also in relation to the growing impact of infectious diseases of iatrogenic origin. Indeed, the increased application of medical practices, such as transplants, which require immunosuppressive treatments, and the growing demand for prosthetic installations, associated with an increasing threat of antimicrobial resistance, have led to a rise in the number of infections of iatrogenic origin, which entails important medico-legal issues. On the other hand, the possibility of detecting minimal amounts of microorganisms, even in the form of residual traces (e.g., their nucleic acids), and of obtaining gene and genomic sequences at contained costs, has made it possible to ask new questions of whether cases of death or illness might have a microbiological origin, with the possibility of also tracing the origin of the microorganisms involved and reconstructing the chain of contagion. In addition to the more obvious applications, such as those mentioned above related to the origin of iatrogenic infections, or to possible cases of infections not properly diagnosed and treated, a less obvious application of forensic microbiology concerns its use in cases of violence or violent death, where the characterization of the microorganisms can contribute to the reconstruction of the case. Finally, paleomicrobiology, e.g., the reconstruction and characterization of microorganisms in historical or even archaeological remnants, can be considered as a sister discipline of forensic microbiology. In this article, we will review these different aspects and applications of forensic microbiology.

Signs of how the Sydney Declaration article is received in the forensic science literature.

The Sydney Declaration is an initiative led by an informal group of forensic scientists with diverse backgrounds. It offers a vision of forensic science based on the trace, as a vestige of a past event related to security or a possible law violation. An article published in Forensic Science International (FSI) introduces to this view [1]. Our investigation delves into how the forensic science literature has received this article (the SD article), nearly two years after its publication. One of the main challenges of this exploratory study was to define the appropriate scope of forensic scientific literature, within which the SD article must be located. In general, the publishing domain is quickly evolving, with many competing players, while still being structured around standard academic disciplines. The forensic literature, meanwhile, is scattered and poorly connected. This reflects the fragmentation of practice and research in forensic science, and the difficulty of situating a scientific activity in such a way as to bring out its forensic substance. Nonetheless, the SD article fills a gap. By deciphering the critical concept of trace, it highlights how pivotal forensic science is in addressing societal challenges. Scholarly literature expresses clear quantitative interest in the SD article. It has received significant qualitative citations on multiple levels and dimensions, in a highly relevant manner and in accordance with its aim of providing a forensic foundation for various debates that have been conducted separately, notably over the last fifteen years.

Optimization of crystal violet technique for enhanced fingerprint detection on various surfaces.

The crystal violet (CV) staining technique represents a prevalent approach for the development of latent fingerprints, especially on adhesive tape surfaces. Nevertheless, the technique necessitates intricate formulations to augment its performance. In this investigation, an optimized CV staining protocol was developed, characterized by the absence of residual dye on the target substrates and the capability of facilitating fingerprint visualization under ambient light conditions. Four donors, comprising two males and two females, deposited natural fingerprints on various substrates, including glass microscope slides, aluminum foil, and 115 g glossy coated paper, without any specific guidelines. Fingerprints developed using cyanoacrylate fuming served as benchmarks and were contrasted with those generated through alternative methods: CV, ardrox, rhodamine 6G, powdering, and the optimized CV staining protocol. The fingerprint development experiment was replicated at seven distinct time intervals, encompassing 1 day, 1 week, 1, 3, 6, 9, and 12 months, resulting in a dataset of 420 fingerprints. The evaluation of fingerprint identifiability employed a scoring system established by the Home Office Centre for Applied Science and Technology. The results indicated that the optimized CV staining technique demonstrated superior performance, boasting a 92.9% rate of identifiable fingerprint development in contrast to other employed methodologies. Consequently, this optimized CV staining approach is recommended as an efficient, rapid, and straightforward critical dyeing method, applicable to a wide array of substrates in forensic investigations.

Kirk's 'Ontogeny of Criminalistics' revisited under the lens of the Sydney Declaration.

The present commentary reviews the considerations of the famous American criminalist Paul Kirk in his seminal publication of 'The Ontogeny of Criminalistics,' written sixty years ago, regarding the status of forensic science and its fundamental principles. Professor Kirk aimed to examine forensic science as an independent scientific discipline, resulting in the identification of six key topics: 1) The need for fundamental principles; 2) the distinction between 'identification' and 'individualization;' 3) the qualifying elements of a profession; 4) the qualifying aspects of a science; 5) the need for a research-oriented basis; 6) the need for application of statistics and probability. In particular, Kirk deemed the nature of the progress made during his time as technical, practical, and transient at the cost of being fundamental, theoretical, and permanent. Predominantly, it is still the case today, with a post-effect fragmentation of forensic science into a myriad of ultra-specialized subdisciplines and applications. The lack of proper articulation of the most fundamental principles of forensic science was one of Kirk's most pressing concerns. The Sydney Declaration aimed to recapture the current fundamental (ontological and epistemological) status of forensic science, resulting in the redefinition of forensic science and its prime object of study, the trace, and in the consolidation of seven principles. The present commentary attempts to address Kirk's arguments in the Ontogeny in the context of the principles of the Declaration, with particular emphasis on the fundamental principles as well as Kirk's distinction between 'identification' and 'individualization,' which is considered critical to understanding the overall scope of forensic science.

Suspected serial killers and unsuspected statistical blunders.

A whole branch of theoretical statistics devotes itself to the analysis of clusters, the aim being to distinguish an apparent cluster arising randomly from one that is more likely to have been produced as a result of some systematic influence. There are many examples in medicine and some that involve both medicine and the legal field; criminal law in particular. Observed clusters or a series of cases in a given setting can set off alarm bells, the recent conviction of Lucy Letby in England being an example. It was an observed cluster, a series of deaths among neonates, that prompted the investigation of Letby. There have been other similar cases in the past and there will be similar cases in the future. Our purpose is not to reconsider any particular trial but, rather, to work with similar, indeed more extreme numbers of cases as a way to underline the statistical mistakes that can be made when attempting to make sense of the data. These notions are illustrated via a made-up case of 10 incidents where the anticipated count was only 2. The most common statistical analysis would associate a probability of less than 0.00005 with this outcome: A very rare event. However, a more careful analysis that avoids common pitfalls results in a probability close to 0.5, indicating that, given the circumstances, we were as likely to see 10 or more as we were to see less than 10.

A "concrete" identification in a dismemberment case.

Homicide perpetrators can use concrete as a means to conceal their victims. When concrete encasement is encountered in the forensic field, albeit rarely, it is often coupled with postmortem dismemberment. This method of obscuring the evidence presents unique investigative obstacles, specifically related to identification. Various approaches to obtaining fingerprints from decedents encased in concrete have been suggested and implemented over the years. The presented case is that of an initially unidentified 44-year-old male, who was subject to postmortem dismemberment and concrete encasement. Meticulous excavation techniques facilitated preservation of evidence and an anatomical reconstruction of the body. These techniques enabled inspection of the incision sites of the dismembered remains during the postmortem examination. Identifiable jewelry and tattoos were noted at autopsy. Further, the resulting concrete molds could be utilized to obtain fingerprints. These prints were used to ultimately identify the decedent.

Bloodstain pattern analysis & Bayes: A case report.

The findings from a bloodstain pattern analysis (BPA) may assist in formulating or falsifying scenarios that are considered in the investigative stages of a criminal investigation. When a case proceeds to trial the bloodstain pattern expert may be asked about the relevance of their findings given scenarios that are proposed by the prosecution and defense counsel. Such opinions provided by an expert are highly relevant to police investigation or legal proceedings, but the reasoning behind the opinion or implicit assumptions made by the expert may not be transparent. A proper framework for the evaluation of forensic findings has been developed since the late twentieth century, based on the hierarchy of propositions, Bayesian reasoning and a model for case assessment and interpretation. This framework, when implemented in casework, mitigates some of the risks of cognitive biases, and makes the reasoning and scientific basis for the opinion transparent. This framework is broadly used across forensic science disciplines. In this paper we describe its application to the field of BPA using a case example from the Netherlands Forensic Institute (NFI).

CRIMINAL OFFENCES RELATED TO ILLICIT TRAFFICKING IN FALSIFIED MEDICINES: INVESTIGATION PROBLEMS.

OBJECTIVE: The aim: Formulate recommendations for improving the efficiency of detection and investigation of trafficking in falsified medicines, application of criminal¬istics knowledge. To analise the contemporary condition and the latest trends in combating this type of crimes and to justify the need for creation of a complex criminalistic methodic investigation. PATIENTS AND METHODS: Materials and methods: Аnalysis of the applicable laws governing trade in medical products in Ukraine; judgments of courts of Ukraine for the period from 2013 to 2022; results of generalization of 128 criminal proceedings; active employee survey results (205 respondents) etc. Over the course of the present research, we have used general scientific and specialised research methods. RESULTS: Results and Conclusions: Increasing the effectiveness of combating the illegal circulation of falsified falsified medicines is a complex problem that encompasses a whole system of directions, requiring the combined efforts of international bodies and organizations, various scientists. One of the priority directions for the introduction of an effective mechanism for combating the distribution of falsified medicines is the development of a complex criminalistic methodic investigation.

Hyperspectral imaging in forensic science: An overview of major application areas.

Analysis of evidence is a challenge. Crime scene materials are complex, diverse, sometimes of an unknown nature. Forensic science provides the most critical applications for their examination. Chemical tests, analytical methods, and techniques to process the evidence must be carefully selected by the forensic scientist. Ideally, it may be interpreted, analyzed, and judged in the original context of the crime scene. In this sense, hyperspectral imaging (HSI) has been employed as an analytical tool that maintains the integrity of the samples/objects for multiple and sequential analysis and for counter-proof exams. This paper is an overview of forensic science trends for the application of HSI techniques in the last ten years (2011-2021). The examination of documents was the main area of exploration, followed by bloodstain analysis aging process; trace analysis of explosives and gunshot residue. Chemometric tools were also addressed since they are crucial to obtain the most important information from the samples. There are great challenges in applying HSI in forensic science, but there have been clear technological and scientific advances, and a solid foundation has been built for the use of HSI in real-life cases.

Utilizing a combined hospital and criminal justice database to identify risk factors for repeat firearm injury or violent-crime arrest among firearm victims.

Introduction: Identifying firearm victims with the greatest risk of repeat-firearm exposure and offering interventions has the potential to disrupt recurrent violence. This study explored risk factors associated with repeat violence among survivors of intentional firearm injury in a unique clinical and criminal justice (CJ) dataset. Methods: This study analyzed a retrospective cohort (n = 4058) of persons injured by nonfatal intentional firearm violence from 2013 to 2016 in one metropolitan area. Data were collected from a single level I trauma center, city police records, and state CJ databases from 1948 to 2019. The primary outcome of interest was another firearm injury or violent-crime arrest (defined as a violent or firearm felony offense). Results: Among 4058 nonfatal intentional firearm victims, 1202 (29.6%) individuals had a repeat-firearm injury or violent-crime arrest. In a bivariate analysis, history of mental, physical, and/or emotional abuse (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.40-1.86), mental health diagnosis (OR, 1.88; 95% CI, 1.51-2.35), or illegal substance use (OR, 2.87; 95% CI, 2.48-3.32) was associated with increased risk of repeat-firearm injury or violent-crime arrest. Prior felony arrest (OR, 3.68; 95% CI, 3.19-4.24), prior incarceration (OR, 3.72; 95% CI, 3.04-4.56), prior firearm charge (OR, 4.06; 95% CI, 3.33-4.96), and suspected gang membership (OR, 8.69; 95% CI, 6.14-12.32) demonstrated the greatest association with significant repeat violence. Conclusions: Thirty percent of those who experienced an intentional firearm injury were found to have a repeat-firearm injury or violent-crime arrest multi-disciplinary interventions that address the complex needs of a CJ-involved population are needed to mitigate significant repeat violence.

The influence of a possible contamination of the victim's clothing on the estimation of shooting distance in mutual shooting incidents.

One of the tools for estimating shooting distance is examination of smokeless powder particle distribution on the target area. Components of the powder that are utilized for this purpose are nitrite anions. The traditional method for detecting nitrite anions mainly involves applying the Griess Test. A known-distance test firing is performed with shootings done at several distances from different targets. The color pattern corresponding to nitrite anions from the crime scene is then compared to the patterns obtained from known distances of the test firing. When a mutual shooting takes place at the crime scene, and a shooter also becomes a shootout victim, it is possible that when examining the shooter as a victim (i.e. target), additional nitrite-containing particles, resulting from his/her shooting, will be present on the shooter-victim clothing. This kind of addition may affect the estimation and practically give a shorter-distance estimation comparing to the actual distance. In this paper, an experimental setup was designed in order to understand if nitrite-containing particles were added to a victim as a consequence of him/her being also a shooter. All of the experiments were predominantly designed to try and minimize the effects of other influencing factors and variables in order to examine if the additions resulting from the firing action affect distance estimation. The experiments involved various types of pistols and distances. The results show that in such a scenario, there are marginal additions of nitrite signals on the victim's shirt. Although the forensic expert's final assessment was within the tolerance interval at all distances, caution should be exercised when attempting to estimate shooting distances in scenarios where the victim also shoots.

How may analysis of an inner layer of clothing affect the scene reconstruction in a shooting incident?

Shooting distances are utilized, among other forensic input, to position shooters and victims at the crime scene. Shooting distance estimation is done, mainly under the knowledge or assumption, that no intervening object has been present between the target and the muzzle. In the analysis of clothing items of victims that have been involved in a shootout, it is assumed that most of the marks and materials are left on the outer layers of clothing. The outer layers, not the inner layers, are the first objects the bullet meets. Consequently, undergarments are often disregarded for shooting distance estimation as they are not assumed to contain sufficient information in the form of marks or materials. In light of the above, it is the standard operating procedure in some forensic laboratories not to examine underwear. In this case report, the forensic examiners started by the implementation of standard operating procedures, thus examining only the outer layers of clothing of the victims. A thorough visual examination of the various clothing items led a forensic examiner to decide to extend the standard operating procedures, and try and examine an undergarment of one of the victims as well. The interpretation of examination products led to different scene reconstruction, one that may have led to a different interpretation of evidence. In this case, simply sticking to standard operating procedures might have led to less accurate crime scene reconstruction. This case report comes to stress the importance of thorough inspection of forensic exhibits, and scientific and critical thinking about different scenarios. Moreover, it demonstrates how the case-by-case approach in shooting distance estimation may add meaningful information, and eventually-bring us even closer to the truth.

The logic of forensic pathology opinion.

Evaluating evidence and providing opinions are at the heart of forensic science, and forensic experts are expected to provide opinions that are based on logically sound and transparent scientific reasoning, and that honour the boundaries of their area of expertise. In order to meet these objectives, many fields of science explicitly apply Bayes' theorem, which describes the logically correct way to update probabilities on the basis of observations. Making a distinction between 'investigative' and evaluative' modes of operating helps to implement the theorem into daily casework. Use of these principles promotes the logic and transparency of the reasoning that leads to expert's opinion and helps the expert to stay within her remit. Despite these important benefits, forensic pathology seems slow to adopt these principles. In this article, we explore this issue and suggest a way forward. We start with a short introduction to Bayes' theorem and its benefits, followed by a discussion of why its application is actually second nature to medical practitioners. We then discuss the difference between investigative and evaluative opinions, and how they enable the forensic pathologist to reconcile Bayes' theorem with the different phases of a forensic investigation. Throughout the text, practical examples illustrate the various ways in which the logically correct way of evidence interpretation can be implemented, and how it may help the forensic pathologist to provide an appropriate and relevant opinion.

Aspects of forensic entomology in forensic medicine.

ntomology, as a vast scientific discipline of zoology, deals with the study of insects, which are an integral part of the ecosystem of our planet and are closely linked to the activity and life cycle of all organisms, including humans. As a result of this natural connection, insects often become a direct “living witness” of a crime and thus an invaluable part of the evidence in a comprehensive forensic investigation, which in such cases necessarily includes a specialized field of science - forensic entomology. The goals of forensic entomology include comprehensive analysis of entomological evidence material and the use of knowledge about insects and other invertebrates for the purpose of investigating and verifying evidence in civil and criminal law. In practice, forensic entomology falls into several categories, including the issue of food pests in industry or agriculture, human and animal parasitology (especially myiasis) and very often the field of criminology and forensic medicine, where the results are mainly applied to determine the length of post mortem interval (PMI), evidence of manipulation of the corpse, or other forensic facts that results from entomological analysis. The conclusions of the entomology study are in many cases an invaluable part of the amount of information that leads to the answer of key questions in complex forensic evidence, especially in the group of serious crimes.

A rapid and nondestructive approach for forensic identification of car bumper splinters using attenuated total reflectance Fourier transform infrared spectroscopy and chemometrics.

The proper identification of car bumper splinters at hit-and-run crime scenes is imperative to forensic investigations, as splinters yield crucial pieces of vehicle information that can lead to subsequent investigation resolution and criminal justice. A method based on attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) combined with Fisher discriminant analysis (FDA) and support vector machine (SVM) is reported to classify car bumper splinters. The FDA and SVM models were constructed based on full spectrum, fingerprint spectrum, and characteristic spectrum data from 156 car bumper splinter samples. The characteristic spectrum data were extracted by principal component analysis. The classification results for different types of data were compared, and the classification models were analyzed. In the FDA, the model based on the spectral data of the characteristic spectrum yielded the highest classification accuracy, and the classification accuracy based on 10 brands was 88.5%. For polypropylene type; polypropylene, talcum powder, and calcium carbonate type; and polypropylene and talcum powder type bumper samples, the classification accuracy rate reached 97.4%. The classification results were ideal for the SVM, for 10 brands and 3 types of samples, the classification accuracy of the model constructed based on both full spectrum and characteristic spectrum data reached 100%. The results suggest that the SVM model is superior to the FDA model. The SVM model is also suitable for the classification of high-dimensional data. ATR-FTIR combined with the chemometrics methods of FDA and SVM is a rapid, nondestructive, and accurate method for the differentiation of car bumper splinters.

Photographic comparison of surface topography as a viable solution when physical match is challenging.

Physical matching methods are a family of well-known methods that are utilized in order to determine whether two pieces of a tearable/breakable material used to be one object. When performing physical match of polymers, it is sometimes difficult to reach an unambiguous conclusion. This is due to various reasons. One is when the tear/fracture resides in an inaccessible or hidden-from-view region of the piece. Another is when the shape of the tear/fracture at the object's tear/fracture line is insufficient for deducing a complete match. Third is deficiency of material along this line. These are examples of processes where the line is affected so drastically, so that a match renders impossible. Specifically, when addressing elastic materials, the tear/fracture line may even be squashed. This may also be a reason for difficulty in performing a physical match. In this paper, a method is proposed where a match is alternatively achieved by means of photographic comparison of marks on the surface topography of the pieces-in-question. Comparisons of pairs of torn pieces of silicon rubber were made. The procedure involved photography of the surface topography the pieces. Then, the photographs were horizontally mirror-flipped. Lastly, a comparison was made between two photographs: a photograph of one piece and a mirror-flipped photograph of the opposite piece. The results show that after comparing the pieces to one another, only one unique pair turned out to be positively matched. Using the proposed method, not only the comparison is done by a more informative method (comparing to physical match), it is also more convenient, faster, less expensive, and technically simpler.

Dictamen médico legal de un análisis de voz, ¿cómo hacerlo? / Medical legal opinion of a voice analysis, how to do it?

La acústica forense es una disciplina de la criminalística que ha alcanzado una ma-durez analítica que obliga a que el perito en análisis de voz se especialice en adquirir conocimientos en fonética, tecnologías de sonido, habla, voz, lenguaje, patologías del habla y la voz, así como procesamiento de la señal sonora. Cuando un dictamen deba ser realizado por un profesional de la salud completamente ajeno a la técnica legal, se tropieza con una falta de protocolos, métodos y procedimientos de trabajo que le permitan entregar un informe técnico, válido y validado para la realización de una entrevista y su posterior análisis comparativo de voces, lo que promueve la necesidad de elaborar una ruta o guía metodológica a través de medios académicos físicos o electrónicos para el desarrollo de este conocimiento y su difusión profesional y científica

Forensic acoustics is a criminalistics discipline that has reached an analytical maturity that requires the expert in voice analysis to specialize in acquiring knowledge in pho-netics, sound technologies, speech, voice, language, speech, and voice pathologies, as well as sound signal processing. When an opinion must be made by a health profes-sional completely unrelated to the legal technique, he encounters a lack of protocols, methods, and work procedures that allow him to deliver a technical, valid, and vali-dated report for conducting an interview and its subsequent comparative analysis of voices, which promotes the need to develop a methodological route or guide through physical or electronic academic means for the development of this knowledge and its professional and scientific dissemination

Characterization of Algerian-Seized Hashish Over Eight Years (2011-2018). Part II: Chemical Categorization.

In Algeria, large quantities of hashish are seized every year. This study aimed to investigate the total content of major cannabinoids in the illicit seized hashish in Algeria over an 8-year period (2011-2018) in order to establish the chemical profile of North African hashish. A total of 3265 hashish samples were analyzed using a validated high-performance liquid chromatography-diode array detection (HPLC-DAD) method, allowing the simultaneous quantification of both the acidic and the neutral forms of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). The results revealed a slight upward trend in the mean THC content, from 7.0% in 2011 to 9.4% in 2018, with an overall mean value of 8.4%. The overall means of CBD and CBN content were 3.5% and 0.8%, respectively. The number of high-potency hashish samples gradually increased to reach 6% in 2018. Two distinct hashish chemotypes were identified: the highly populated chemotype II, corresponding to the traditional medium-potency hashish ([THC + CBN]/CBD ~ 2.16), and chemotype I, containing hashish samples of relatively high THC levels and low levels of CBD (ratio ~ 4.90). Both chemotypes I and II were characterized in the ternary plot, and the proportions (THC:CBD:CBN) were about 85%:13%:2% and 60%:35%:5%, respectively.

Characterization of Algerian-Seized Hashish Over Eight Years (2011-2018). Part I: Physical Categorization.

Data on the physical characteristics of North African hashish are scarce. This article exploits hashish seizure data collected over an 8-year period (2011-2018) in Algeria in order to establish a physical profile of North African hashish. The collected data were subjected to statistical analysis in order to characterize the three main forms in which North African hashish is packaged, namely hashish bags, hashish packets, and hashish units (slab bars). The study revealed that 82% of hashish bags weigh 25 kg that hashish bags are made either as a handbag or as a back bag that they are most often wrapped with woven plastic. Two hashish bag configurations were identified-Bag-Packet-Unit (79%) and Bag-Unit (21%)-and 81% of the total studied bags featured logos. Hashish packets contain the units, which are wrapped with three to five different types of packaging to constitute packets of 0.5 kg (65%) or 1 kg (32%), with two different configurations including 100- or 250-g units. Hashish packets are mainly covered with adhesive tape, and only 18% of them feature inscriptions. Hashish units are found in three different shapes: slab bar (most common), soap bar, and egg-shaped bar. Sixty-five percent of the North African hashish slab bars have a weight of 100 g; other weights are 250 g (20%), 90 g (10%), and 200 g (2%). Most of the 90-100 g units have a light brown color, and 200-250 g units are dark brown in color. Sixty-four percent of hashish units contain logos. Five logo classes were identified: letters (37%), numbers (27%), symbols (23%), animals (11%), and, more recently, "paper logos" at just 2%, exclusively reserved for high-quality hashish and entirely intended for the European market. The findings of this work allow for the establishment of a profiling platform of hashish seizures in this region and can be generalized to all countries that report this region as the primary source of seized hashish within their territory.

The Analysis of 3D Printer Dust for Forensic Applications,.

3D printers are becoming increasingly efficient and economical, and thus more widespread and easily accessible to consumers and businesses. They have been used to print nefarious objects such as guns and suppressors. Previous research has documented the release of dust particles during the printing process; however, little has been written about the morphology and chemical features that define the dust emitted by these printers. This study was undertaken to recover, analyze, and identify the dust produced during the printing process in the context of forensic trace evidence analysis. Samples were collected from a variety of 3D fused deposition modeler printers, representing both consumer and commercial grade models. This work focused on printers that use thermoplastic filaments composed of acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), two of the most commonly used filament polymers. Swabs were used to collect dust within the printer chamber and then processed to isolate the dust particles. Particles produced from ABS filaments are most easily recognized via light microscopy through a combination of color, morphology, and fluorescence. The composition of these particles can be confirmed through analysis by either FTIR or Raman microspectroscopy. These methods can also be used to identify ABS fillers and pigments within the printer dust particles. In contrast, dust from PLA printers consistently contained finer, submicron-sized particles that could be observed by field emission scanning electron microscopy. Because the size of the particles precludes their identification using vibrational spectroscopy methods, pyrolysis-GC-MS was used to confirm the presence of PLA.