Articles
Forensic pathology
2022
Keith A. Findley & Dean A. Strong, Ending Manner of Death Testimony and Other Opinion Determinations of Crime, University of Wisconsin Law School, Legal Studies Research Paper Series Paper No. 1737
This article explains the conflict between evidentiary standards and the manner of death testimony provided by medical examiners. The authors discuss the different facts that need to be considered by the medical examiner to determine the manner of death in a case. The article argues that these facts are ‘non-medical’ and therefore the opinion on manner of death is beyond the medical expertise of the examiner.
Serology
2017
Ashutosh Sharma, Sensitivity of phenolphthalein and benzidine tests in field of Forensic Sciences, International Journal of Research Culture Society, ISSN: 2456-6683 Volume - 1, Issue - 4, June - 2017
The aim of this study was to examine the sensitivity of two presumptive tests -benzidine and phenolphthalein (Kastle Mayer) tests for identification of blood at crime scenes. The tests were performed on various vegetable and fruit extracts such as garlic, dhania, peas, apple and banana. The tests were also performed on other items such as rust and ferrous sulphate. The study showed that benzidine was more sensitive than phenolphthalein as it gave most false positive results when tested on vegetables and fruits. These presumptive tests are based on a change in colour which is observed when the reagents are added to the blood sample. This change is due to the chemical reaction that occurs in the presence of an enzyme found in blood. Similar enzymatic reaction is also observed in substances other than blood such as certain vegetables, rust, etc. Therefore, the sole use of presumptive tests can lead to false identification as the change in colour can be from substances other than blood. This study concluded that phenolphthalein is better suited for crime scene samples than benzidine as a presumptive test.
Renata Inzinna Bernardo Fonseca, et al, Actual trends in the use of the kastle-meyer test: applications in different species and verification of the limit of detection of sensitivity and vestigiality, Journal of Dairy, Veterinary & Animal Research 8(4):166
In this article, phenolphthalein presumptive test (Kastle-Meyer test) is tested against human, dog and cat blood. When the reagent was added to the sample, change in colour was observed in all three cases giving a positive result for the test. Positive results were observed in human and dog blood samples for dilutions upto 1:10000, whereas for cat blood samples, a positive result was observed for dilutions upto 1:1000. The study notes that these results were expected as humans, cats and dogs are mammals. Their red blood cells contain residue of enzyme peroxidase which decomposes the hydrogen peroxide (present in the Kastle-Meyer reagent) to generate a pink colour. This study highlights that presumptive tests for detection of blood are unable to distinguish between animal and human blood.
SERATEC, PSA in body fluids
Since semen contains high concentration of prostate specific antigen, the Prostate Specific Antigen (PSA) test is used to detect the presence of semen. However, studies have shown that the PSA can be found in sources other than semen and has even been found in other male and female body fluids. This overview for users of the SERATEC® PSA SEMIQUANT Tests, discusses the presence and concentration of PSA in male and female bodily fluids. This work is important to highlight that PSA can be detected in sources other than semen.
Ajay SR, Priyanka V, Hiren V, Priyanka M. Study on Acid Phosphatase Enzyme Activity in Semen Mixed with Various Body Fluids. J Forensic Sci & Criminal Inves. 2019; 11(5): 555823.
Acid Phosphatase test is a presumptive test used for detection of semen from crime scene samples. In the presence of acid phosphatase reagents, semen stains change colour to purple. The aim of the study is to observe the activity of acid phosphatase in the presence of other body fluids. This is important because semen samples found at a crime scene may be mixed with other body fluids as well. From this study it is concluded that as the serial dilutions of semen samples with various body fluids progresses, the time of reaction also increases. The results showed that when the semen gets mixed with other body fluids there is a decrease in the dilution limit to which acid phosphatase enzyme can be detected. Thus the paper concludes that a sample requires further confirmatory testing, as acid phosphatase is a presumptive test and should not be solely relied upon for positive identification of semen.
R. S. Higaki And W. M. S. Phiilp, A study of the sensitivity, stability and specificity of phenolphthalein as an indicator test for blood, Can.Soc.Forens.Sci.J.Vol.9,No.3(1976)
This paper examined and compared phenolphthalein and benzidine reactions for their sensitivity and specificity. For the phenolphthalein test, a drop of phenolphthalein was first added to the sample and hydrogen peroxide was added a few seconds later. If a colour change is observed after the addition of hydrogen peroxide, the result was deemed as a positive. One of the factors that was examined was the specificity of these presumptive tests. For this, the reagents were tested against fourteen types of vegetable material, milk, household cleaners and various types of paper. Benzidine gave positive results for most of the vegetable material. Only two of the materials tested, manila paper and tincture of iodine gave positive results before the addition of peroxide. In the case of manila paper,a dark red color was obtained which highlighted that phenolphthalein should not be used in suspected stains of this type. Tincture of iodine produced a weaker positive before the addition of peroxide highlighting that the one stage test should not be used because of its reduced specificity. This study highlights that phenolphthalein gives better results as compared to benzidine when used as a presumptive test.
Admissibility Standards for Forensic Evidence
2018
Paul C Giannelli, Forensic Science: Daubert’s Failure, Case Western Reserve Law Review
This article examines the framework for evaluation of scientific evidence as set out in the U.S Supreme Court decision Daubert v. Merrell Dow Pharmaceuticals Inc (1993). The Daubert standard for admissibility of scientific evidence has been considered revolutionary for introducing concepts of empirical testing, peer review and publication, error rates and maintenance of standards to the already established standard of general acceptance. The author evaluates different forensic disciplines such as bitemark comparison, fingerprints firearm analysis, arson investigation and hair microscopy against the Daubert standard. The author finds that despite the scrutiny under Daubert, unreliable forensic evidence continues to be admitted in legal proceedings and the judiciary has been unable to fulfill its gatekeeping duties. The article concludes that the lack of independent scientific research and expertise into the validity and reliability of different forensic disciplines allows such flawed evidence to be admissible.
2014
Gary Edmond et al., How to cross-examine forensic scientists: A guide for lawyers, Australian Bar Review
This article is a guide for lawyers to cross examine forensic experts and challenge forensic evidence submitted in a case. It explains the traditional principles such as admissibility, relevance, probative value in the context of forensic evidence. The article also describes how limitations of the scientific method, error rates, proficiency, review process, cognitive bias and accurate expression of opinion can be explored in cross-examination. It explains how scientific research and expertise can be used to build legal arguments. Finally, it urges lawyers to examine admissibility and relevance of evidence through rigorous cross examination to ensure that the pursuit of truth is secured by disregarding unreliable evidence.
2014
Gary Edmond et al., Admissibility Compared: The Reception of Incriminating Expert Evidence (i.e., Forensic Science) in Four Adversarial Jurisdictions, U Den Crim L Rev
This article compares the admissibility standards for forensic science evidence across four jurisdictions i.e. the United States, England and Wales, Canada and Australia. The authors compare the rules, jurisprudence and the practice involving admission of such expert opinion in a criminal trial. The article focuses on latent fingerprint, DNA, bite mark comparison and audio-visual evidence. The use of unreliable forensic evidence was found in jurisdictions despite the presence of formal admissibility standards based on testing the reliability of expert evidence. The article suggests that judges should be better gatekeepers for unreliable evidence by developing more interest in the empirical studies and reviewing their court practices. The article also calls for more research in areas of foundational validity and reliability of forensic evidence.
2009
Kent Roach, Forensic Science and Miscarriages of Justice: Some Lessons from Comparative Experience, Jurimetrics Journal
This article critically assesses the National Research Council's (NRC) 2009 report in light of comparative experience in Australia, Canada, and the United Kingdom. It critiques the lack of comparative analysis in the NRC report and its pessimistic view of the contributions that courts can make under the Daubert standard to exclude unreliable forensic evidence. While acknowledging that the NRC report is an important step towards forensic science reform, the article doubts the workability of the NRC's unified vision of forensic science in any federal system, especially one that is as decentralized as the United States.
Interpretation of Forensic Evidence
2019
Justice Chris Maxwell, Preventing miscarriages of justice: The reliability of forensic evidence and the role of the trial judge as gatekeeper, (2019) 93 ALJ 642
. This paper explains the gatekeeping role that trial judges play in ensuring that only relevant and reliable forensic evidence is admitted in court. The author explores the need for greater scientific literacy within the legal profession and discusses the steps that the Australian judiciary has taken towards introducing better standards for examining forensic evidence.
2018
H J Swofford and J G Cino, Lay Understanding of "Identification": How Jurors Interpret Forensic Identification Testimony, Journal of Forensic Identification
This study evaluates how the term ‘identification’ is interpreted by lay persons. The study stems from the ongoing debate about the terms used by experts in their reports, which may offer more weight to the forensic evidence than what has been empirically demonstrated. As part of this study, 300 lay persons who are potential jury members were polled. Two separate surveys, each consisting of a single question was given to the participants. Based on this, the authors’ found that approximately 71% of potential jurors may interpret expert testimony containing the word "identification" (or "identified") to imply a single source attribution "to the exclusion of all others". This study is an attempt to show how lay person or potential jurors may misinterpret the term ‘identification’ when used in the context of scientific evidence and expert opinion.
2017
Jeff Kukucka et al., Cognitive Bias and Blindness: A Global Survey of Forensic Science Examiners, Journal of Applied Research in Memory and Cognition
The study is aimed to measure the consensus amongst forensic examiners on a range of bias-related issues. Through a survey of forensic examiners across various jurisdictions, the study evaluates whether examiners differ in their beliefs about bias as a function of their experience or domain of specialization. Methodology for this study also included comparison of the beliefs of bias-trained and untrained examiners. The sample included 403 professional forensic examiners (219 women, 183 men, and one who did not report gender).The study observed that 148 examiners (36.7% of the total sample) reported a belief that their own judgments are 100% accurate. 22.4% of the examiners who believed that cognitive bias is a cause for concern in the forensic sciences as a whole, believed that bias is not a concern in their own domain. Similarly, 31.10% of those who believed that cognitive bias is a cause for concern in their own domain also believed that their own judgments are not influenced by bias. 68.8% of the sample agreed (either strongly, moderately, or slightly) that an examiner’s expectations can influence their analysis.
2010
I E Dror and S A Cole, The Vision in “Blind” Justice: Expert Perception, Judgment, and Visual Cognition in Forensic Pattern Recognition, Psychonomic Bulletin & Review
The article examines multiple studies conducted to evaluate various factors that affect the perception and judgement of forensic examiners involved in pattern recognition and identification. As per current research, external factors such as emotional context and motivation influence the decision making process. Decisions involving pattern recognition and identification are subjective and susceptible to influences. The same expert with the same set of prints could reach a different conclusion, depending on the information and context provided to them. The results of the studies were also impacted depending on whether the participants knew they were being tested or not. The authors conclude that decision making involved in the forensic pattern recognition and identification is vulnerable to cognitive bias, and further research is required to understand the influence on external factors on it.
2009
Simon A Cole, Forensics Without Uniqueness, Conclusions Without Individualization: The new Epistemology of Forensic Identification, Law, Probability and Risk
This article uses latent print evidence to analyse the concept of forensic identification and theories surrounding individualisation and uniqueness. It states that statements about uniqueness are often used to justify exaggerated claims that are part of any expert opinion. While these are not based in scientific research, they have become an integral part of expert opinions on forensic identification. The author argues that instead of individualisation, the probative value of forensic evidence should be reported with transparency, precision and conservatism. The article concludes that as uniqueness remains unproven, it should be discarded and not be used to justify individualisation. Resources should instead be invested in researching better articulation for forensic identification.
2008
Michael J Saks and Jonathan J Koehler, The Individualization Fallacy in Forensic Science Evidence, Vanderbilt Law Review
This article breaks down the two main steps of forensic identification i.e. comparing a questioned sample to a known sample followed by the assessment of the reported match. The authors find that historically different forensic disciplines have evolved from invalidated assumptions of individualisation, where claims to individuality or rarity are made without any rigorous scientific research. They conclude that forensic examiners often provide exaggerated and definitive opinions without any scientific justification. The article challenges the conventional theory of forensic identification on the ground that the individualisation inherent to this practice cannot be proved without any supporting scientific evidence, which must be developed through empirical research for many forensic disciplines.