Forensic Articles

We first begin with an artificial intelligence approach to crime scenario modelling once a dead body has been found. We then turn to a panoply of contexts and approaches to the processing of human faces: face recognition methods and tools for identification; foreseeing how aging would affect a face (e.g., of a child who went missing); facial expression recognition; digital image forensics (with doctored photographs); facial reconstruction from skeletal remains; and factors in portraiture analysed in the TIMUR episodic formulae model. Having begun with these two major areas (crime scenario modelling, and face processing), we take a broad view of the forensic disciplines of expert opinion, and the sometimes controversial role of statistics in them. We then consider the contribution to forensic science of anthropology and archaeology, as well as software tools for human anatomy. Next, we turn to forensic geology and techniques from geophysics; scent-detection and electronic noses; forensic palynology and its databases; computing in environmental forensics; and forensic engineering. Two large sections, each internally subdivided into nine units, conclude this chapter: “Individual Identification”, and “Bloodstain Pattern Analysis, and the Use of Software for Determining the Angle of Impact of Blood Drops”. The former begins with a history of identification methods, and continues with DNA evidence, and a controversy among statisticians concerning this; we then discuss human fingerprints, and growing skepticism concerning reliability of identification by fingerprints. We then turn to computational techniques for fingerprint recognition, and having surveyed these, we proceed to describe in detail two such techniques.

Sexual assaults create significant health and legislative problems for every society. All health professionals who have the potential to encounter victims of sexual assaults should have some understanding of the acute and chronic health problems that may ensue from an assault. However, the primary clinical forensic assessment of complainants and suspects of sexual assault should only be conducted by doctors and nurses who have acquired specialist knowledge, skills, and attitudes during theoretical and practical training.

This review presents the basic problems and currently available molecular techniques used for genetic profiling in disaster victim identification (DVI). The environmental conditions of a mass disaster often result in severe fragmentation, decomposition and intermixing of the remains of victims. In such cases, traditional identification based on the anthropological and physical characteristics of the victims is frequently inconclusive. This is the reason why DNA profiling became the gold standard for victim identification in mass-casualty incidents (MCIs) or any forensic cases where human remains are highly fragmented and/or degraded beyond recognition. The review provides general information about the sources of genetic material for DNA profiling, the genetic markers routinely used during genetic profiling (STR markers, mtDNA and single-nucleotide polymorphisms [SNP]) and the basic statistical approaches used in DNA-based disaster victim identification. Automated technological platforms that allow the simultaneous analysis of a multitude of genetic markers used in genetic identification (oligonucleotide microarray techniques and next-generation sequencing) are also presented. Forensic and population databases containing information on human variability, routinely used for statistical analyses, are discussed. The final part of this review is focused on recent developments, which offer particularly promising tools for forensic applications (mRNA analysis, transcriptome variation in individuals/populations and genetic profiling of specific cells separated from mixtures).

Crime Laboratories routinely process evidence from criminal cases for the presence of biological fluids such as blood, semen, and saliva in order to obtain DNA profiles. Forensic Biology encompasses both Forensic Serology and DNA testing. Prior to examination, it is important for the forensic scientist to evaluate the type of crime and the samples submitted so that the evidence can be processed in the proper order for the type of testing needed. Typically, evidence will be analyzed using a mix of presumptive and confirmatory tests to determine the presence of biological stains prior to DNA analysis, although this may not always be feasible when the amount of sample is limited. These Forensic Serology tests assist the analyst in determining which samples will go forward to DNA testing. Forensic DNA testing in most crime laboratories in the United States is done using short tandem repeat (STR) analysis of the 13 core CODIS STR loci. This chapter introduces routine serology procedures, the DNA testing process, the interpretation of DNA profiles, and the national DNA database, CODIS.

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Wildlife DNA forensics is receiving increasing coverage in the popular press and has begun to appear in the scientific literature in relation to several different fields. Recognized as an applied subject, it rests on top of very diverse scientific pillars ranging from biochemistry through to evolutionary genetics, all embedded within the context of modern forensic science. This breadth of scope, combined with typically limited resources, has often left wildlife DNA forensics hanging precariously between human DNA forensics and academics keen to seek novel applications for biological research. How best to bridge this gap is a matter for regular debate among the relatively few full-time practitioners in the field. The decisions involved in establishing forensic genetic services to investigate wildlife crime can be complex, particularly where crimes involve a wide range of species and evidential questions. This paper examines some of the issues relevant to setting up a wildlife DNA forensics laboratory based on experiences of working in this area over the past 7 years. It includes a discussion of various models for operating individual laboratories as well as options for organizing forensic testing at higher national and international levels.

PCR is an important and powerful tool in several fields, including clinical diagnostics, food analysis, and forensic analysis. In theory, PCR enables the detection of one single cell or DNA molecule. However, the presence of PCR inhibitors in the sample affects the amplification efficiency of PCR, thus lowering the detection limit, as well as the precision of sequence-specific nucleic acid quantification in real-time PCR. In order to overcome the problems caused by PCR inhibitors, all the steps leading up to DNA amplification must be optimized for the sample type in question. Sampling and sample treatment are key steps, but most of the methods currently in use were developed for conventional diagnostic methods and not for PCR. Therefore, there is a need for fast, simple, and robust sample preparation methods that take advantage of the accuracy of PCR. In addition, the thermostable DNA polymerases and buffer systems used in PCR are affected differently by inhibitors. During recent years, real-time PCR has developed considerably and is now widely used as a diagnostic tool. This technique has greatly improved the degree of automation and reduced the analysis time, but has also introduced a new set of PCR inhibitors, namely those affecting the fluorescence signal. The purpose of this chapter is to view the complexity of PCR inhibition from different angles, presenting both molecular explanations and practical ways of dealing with the problem. Although diagnostic PCR brings together scientists from different diagnostic fields, end-users have not fully exploited the potential of learning from each other. Here, we have collected knowledge from archeological analysis, clinical diagnostics, environmental analysis, food analysis, and forensic analysis. The concept of integrating sampling, sample treatment, and the chemistry of PCR, i.e., pre-PCR processing, will be addressed as a general approach to overcoming real-time PCR inhibition and producing samples optimal for PCR analysis.

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