**Reliability and Probative Value**

Key aspects of the evaluation of forensic science and forensic medicine are the concepts of reliability and validity. While validity focuses upon the accuracy of a measure, in forensic matters reliability tends to be the more important issue in terms of the value of expert evidence. Evaluation of the reliability of expert opinion evidence is controversial in all countries and there are diverse yardsticks by which it can be measured, including formal recourse to factors such as falsifiability, error rate, extent of publication in recognised, peer-reviewed journals and reputation amongst colleagues in the same field. When areas are "novel" in the sense of still emerging from the iconoclastic or emerging toward the generally accepted by reference to objective criteria, there can be a tension between the actual techniques and the theories underlying them and the prejudicial effect that they may exert on courts (especially jurors) called upon to evaluate them. This can be so for countries that utilise admissibility criteria for such evidence but also for countries that focus upon the need to determine the probative value of such evidence.

In all such instances, there is a need for scientific and medical rigor with the employment of standardised methods, criteria for interpretation and retention of primary samples for re-testing as required. The caliber of those who undertake the forensic work is critical, as is the quality of the testing facilities, and adherence to ethical probity in disclosure and interpretation of results that may be other than criminal investigators are hoping for. There is always a need for transparency of processes and candid acknowledgment of the status of techniques and theories that as yet may not have fully fledged statistical bases enabling definitive interpretation of test results. In such scenarios courts and tribunals need to exercise circumspection in the reliance that they place upon such evidence, ensuring that witnesses giving evidence about such matters are made accountable for the opinions that they express. This highlights the need for legal practitioners to make themselves sufficiently familiar with the controversies about and limitations in scientific and medical techniques to be able to ask probing questions that expose parameters of expertise and accuracy.

### **The Chapters**

**II**

**Chapter 8 123**

Forensic Medicine **133**

**Chapter 9 135**

**Chapter 10 159**

**Chapter 11 175**

Salivary Analysis for Medico-Legal and Forensic Toxicological Purposes

Obstetric Markers as a Diagnostic Forensic Tool *by Adithi Shetty and B. Suresh Kumar Shetty*

Pharmacogenetics and Tramadol-Related Fatalities *by Sanaa M. Aly, Jean-Michel Gaulier and Delphine Allorge*

**Section 4**

*by Roberto Scendoni*

Herbal Drugs Forensic

*by Shalvi Agrawal and Astha Pandey*

The book begins with a review by Freckelton (Chapter 1) of the controversial and emerging area of **forensic gait analysis evidence**, which is given by practitioners from a number of disciplines, including podiatry, photogrammetry, biomechanics and anatomy, and has been the subject of diverse judicial decisions about admissibility in Canada, the United

Kingdom and Australia. The conclusion reached by the chapter is that the reception of forensic gait analysis evidence by the courts is dangerous and, as yet premature, until further development of statistically rigorous databases of gait characteristics.

Al-Dalmoshi et al. (Chapter 2) explain the ways in which **mitochondrial DNA** has the potential to be an important tool for human identification and differentiating between human and animal blood at crime scenes. In extreme conditions nuclear DNA is adversely affected or even destroyed, but mitochondrial DNA has characteristics that can be valuable for forensic purposes; amongst other things, it contains multiple copies and resists harsh and unstable conditions. It can be of particular utility in investigating blood sports and the provenance of blood samples found in diverse crime scenes.

Sahajpal et al. (Chapter 3) identify the threat to the environment and biodiversity from the commission of crimes involving wildlife. They note also the monetary values of the illegal trade in wildlife and therefore the temptation for the unscrupulous to engage in conduct that jeopardises the viability of many species. They review the three most frequently used techniques in **wildlife forensic investigation:** microscopy, DNA analysis and isotope analysis. They observe that some of the techniques employed in wildlife forensics require standardisation and that there are particular analytical challenges when evidentiary material is very limited.

Ioganson et al. (Chapter 4) review the reliability and reproducibility of **DNA profiling from degraded samples** by reference to extensive experience with analysis of bones and tissues in unidentified corpses in Russia.

Knoops (Chapter 5) describes the relatively new DNA technique of **probabilistic genotyping**, which has the potential to provide a determination of complex DNA profiles from multiple contributors. The author compares its utility to that of mainstream DNA techniques such as Combined Probability of Inclusion. The chapter highlights the potential pitfalls in traditional DNA test results where the samples are complex, as well as the importance of the information provided to the DNA tester. The chapter also emphasises the potential for probabilistic genotyping to correct wrongful convictions and to discern the real perpetrator of a crime where there are a number of suspects.

Kumar et al. (Chapter 6) demonstrate the many ways in which **tool mark analysis** can be utilised in criminal investigations. They review contemporary methods for forensic tool mark analysis and interpretation, noting that it can constitute an adjunct for contributions as diverse as anthropology, archaeology and pathology. They identify the need for forensic examination to be rational, unambiguous, balanced and rigorous.

Garg et al. (Chapter 7) review methods in **forensic osteology** for identifying deceased persons by reference to race, age and sex from bones. They argue that the discipline has emerged as an important means of identification within the criminal justice system and explain how certain bones can provide information about gender, race and other individualising characteristics relevant to criminal investigations.

Shetty and Shetty (Chapter 8) describe the field of **forensic diagnostics**, utilising biomarkers. They identify that pregnancy diagnosis from traces of blood can assist in finding a missing woman who is pregnant and in investigating illegal abortions. They also review the evidence for the utility of the technique for investigating sexual assaults, maternal substance abuse and paternity testing.

Scendoni (Chapter 9) reviews the literature on the forensic application of **saliva testing** as an alternative biological matrix to blood for the determination of xenobiotics and/ or drugs of abuse and their metabolites in both the living and the dead. He highlights

**V**

recognised and potential forensic issues in the testing of saliva from a toxicological and medico-legal perspective, concluding that it requires highly qualified personnel who are able to apply analytical methods and interpret results in the light of up-to-date knowledge, and toxicological laboratories equipped with state-of-the-art instrumentation.

Aly et al. (Chapter 10) review the phenomenon of Tramadol-caused deaths and the potential for molecular autopsies to assist investigations into such drug-related deaths. They argue that **pharmacogenetic** and **toxicological investigations** can assist clinicians and courts alike by predicting and identifying adverse consequences from

Agrawal and Pandey (Chapter 11) conclude the collection, describing the emerging area of **forensic analysis of herbal medications**. They point out that patients are often unaware of the authenticity of drugs marketed as herbal, but that such medications may be adulterated by a range of products. This means that there is a significant public health need (especially in the time of COVID-19) to investigate the bioconstituents of such drugs. However, the authors acknowledge that forensic analysis of herbal medications is in its early stages and as yet its methodology needs to be standardised and validated.

*Forensic Analysis - Scientific and Medical Techniques and Evidence under the Microscope* is an innovative and contemporary international collaboration by scholars in medicine, science and law. It does not purport to be the last or the authoritative word on any of the diverse medical, scientific or legal issues that it canvasses. My hope as its editor is that it raises new issues, provides helpful information about emerging and conventional areas of forensic medico-scientific investigation, and gives a fillip to the development of rigorous international standards so that expert opinion evidence utilised by criminal investigators and relied upon by the courts will be both reliable and valid. In these circumstances, miscarriages of justice will be minimised, the respect of the community for the legal system will be vindicated, and the integrity of the many disciplines of

**Ian Freckelton AO QC**

Supreme Court of Nauru, Republic of Nauru

Professor of Law and Psychiatry, University of Melbourne,

Adjunct Professor of Forensic Medicine,

Castan Chambers, Melbourne, Australia

Monash University,

Adjunct Professor, Johns Hopkins University,

United States

Barrister,

Judge,

Australia

Australia

the administration of medications such as Tramadol.

forensic science and medicine will be enhanced.

**Aspirations of the Book**

recognised and potential forensic issues in the testing of saliva from a toxicological and medico-legal perspective, concluding that it requires highly qualified personnel who are able to apply analytical methods and interpret results in the light of up-to-date knowledge, and toxicological laboratories equipped with state-of-the-art instrumentation.

Aly et al. (Chapter 10) review the phenomenon of Tramadol-caused deaths and the potential for molecular autopsies to assist investigations into such drug-related deaths. They argue that **pharmacogenetic** and **toxicological investigations** can assist clinicians and courts alike by predicting and identifying adverse consequences from the administration of medications such as Tramadol.

Agrawal and Pandey (Chapter 11) conclude the collection, describing the emerging area of **forensic analysis of herbal medications**. They point out that patients are often unaware of the authenticity of drugs marketed as herbal, but that such medications may be adulterated by a range of products. This means that there is a significant public health need (especially in the time of COVID-19) to investigate the bioconstituents of such drugs. However, the authors acknowledge that forensic analysis of herbal medications is in its early stages and as yet its methodology needs to be standardised and validated.
