Gill Misleading DNA Evidence

Reasons for Miscarriages of Justice
1. Auflage 2014
ISBN: 978-0-12-417220-3
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 100 Seiten

Misleading DNA Evidence: A Guide for Scientists, Judges, and Lawyers presents the reasons miscarriages of justice can occur when dealing with DNA, what the role of the forensic scientist is throughout the process, and how judges and lawyers can educate themselves about all of the possibilities to consider when dealing with cases that involve DNA evidence. DNA has become the gold standard by which a person can be placed at the scene of a crime, and the past decade has seen great advances in this powerful crime solving tool. But the statistics that analysts can attach to DNA evidence often vary, and in some cases the statistical weight assigned to that match, can vary enormously. The numbers provided to juries often overstate the evidence, and can result in a wrongful conviction. In addition to statistics, the way the evidence is collected, stored and analyzed can also result in a wrongful conviction due to contamination. This book reviews high-profile and somewhat contentious cases to illustrate these points, including the death of Meredith Kercher. It examines crucial topics such as characterization of errors and determination of error rates, reporting DNA profiles and the source and sub-source levels, and the essentials of statement writing. It is a concise, readable resource that will help not only scientists, but legal professionals with limited scientific backgrounds, to understand the intricacies of DNA use in the justice system. - Ideal reference for scientists and for those without extensive scientific backgrounds - Written by one of the pioneers in forensic DNA typing and interpretation of DNA profiling results - Ideal format for travel, court environments, or wherever easy access to reference material is vital

Dr. Peter Gill joined the Forensic Science Service (FSS) in 1982. He began his research into DNA in 1985, collaborating with Sir Alec Jeffreys of Leicester University. In the same year they published the first demonstration of the forensic application of DNA profiling. In 1987, Dr. Gill was given an award under the civil service inventor's scheme for discovery of the preferential sperm DNA extraction technique and the development of associated forensic tests. He was employed as Senior Principal Research Scientist at the Forensic Science Service (FSS). Currently, he hold concurrent positions at Oslo University Hospital and the University of Oslo where he is Professor of Forensic Genetics.RomanovsIn 1993-4, Dr. Gill was responsible for leading the team which confirmed the identity of the remains of the Romanov family, murdered in 1918, and also the subsequent investigation which disproved the claim of Anna Anderson to be the Duchess Anastasia (using tissue preserved in a paraffin wax block for several decades). This was an early example of an historical mystery that was solved by the analysis of very degraded and aged material, and was one of the first demonstrations of low-template DNA analysis.Low-template DNAIn relation to the above, Dr. Gill was responsible for developing a routine casework-based 'super-sensitive' method of DNA profiling that was capable of analysing DNA profiles from a handful of cells. This method was originally known as low-copy-number (LCN) DNA profiling. Now it is known as Low template DNA profiling. New statistical methods and thinking were also developed to facilitate the new methods. National DNA databaseDr. Gill was responsible for leading the team that developed the first multiplex DNA systems to be used in a National DNA database anywhere in the world, and for the design of interpretation methods that are in current use (c.1995).Court reporting: Dr. Gill has been involved with giving evidence in several high profile (controversial) cases - including the Doheny / Adams appeals, and the Omagh bombing trial in the UK.Membership of scientific societiesCurrently, Dr. Gill is a member of the European Network of Forensic Science Institutes and ex-chair of the 'methods, analysis and interpretation sub-section' He is chair of the International society for forensic genetics DNA commission on mixtures and has written a number of ISFG recommendations on low-template, mixture interpretation and evaluation of evidence that are highly cited. D. Gill is a member of the European DNA Profiling Group (EDNAP). He has published more than 200 papers in the international scientific literature which have been cited more than 20,000 times - many of these are collaborative papers under the auspices of ISFG, EDNAP and ENFSI. He is the recipient of the 2013 Scientific Prize of the International Society for Forensic Genetics.Affiliations and ExpertiseForensic Genetics Research Group, Oslo University Hospital; Institute of Clinical Medicine, University of Oslo, Norwa

Autoren/Hrsg.

Gill, Peter

Leseproben

Chapter 2

A Deep Analysis of the Basic Causes of Interpretation Errors

Abstract

This chapter provides examples of errors of thinking that have resulted in miscarriages of justice. A comparison of the wrongful arrest of Adam Scott (UK) with R v Jama (Australia) shows that there are many features that are in common between the two cases. It should be possible to alter practice in order to reduce chance of recurrence of similar errors propagated in casework. Because laboratory errors are a fundamental reason for mistakes, it is recommended that proficiency testing is routinely applied, along with declaration of error rates, so that evidence is interpreted in perspective of laboratory performance. The “framework of propositions” is discussed in detail: it is often appropriate to report at the “sub-source” level, i.e., no implicit assumptions can be made about the association of the DNA profile with the body fluid of origin or the “activity” that resulted in the transfer of the DNA. Examples are provided where DNA profiles are reported at an inappropriate level in the “framework of propositions.” A statement format is introduced to avoid the problems identified.

Keywords

Miscarriages of justice

Framework of propositions

Proficiency testing

Laboratory errors

Contents

2.1 An Exemplar Case: Adam Scott   21

2.2 The Miscarriage of Justice in R. v. Jama   27

2.3 Characterization of Error   30

2.4 Determination of Error Rates   36

2.5 Reporting DNA Profiles at Sub-Source Level   40

2.6 Reporting DNA Profiles at Source Level   41

2.7 Activity Level Reporting   46

2.8 The Role of the Prosecution Authorities   54

2.9 The Role of the Accreditation/Regulatory Authorities   55

2.10 The Database Trawl Problem   56

2.11 The Lessons of History   58

2.12 The Essentials of Statement Writing   59

2.13 Summary   64

2.1 An Exemplar Case: Adam Scott

A recent UK regulator’s report (Rennison, 2012) provides a detailed insight into a case where a man was wrongfully arrested and charged with the crime of rape. The errors were identified before a trial could occur.1 It is important to understand the reasons for the errors and to understand the implicit dangers. For every error discovered, there are an unknown number that are undiscovered.

The circumstances can be summarized as follows: the laboratory analyzed the case using the SGM plus system and obtained a partial (17 allele)2 DNA profile that was reported with strength of evidence of one in one billion in favor of the prosecution hypothesis. This evidence was sufficient for the prosecution authorities to issue an arrest warrant and the individual was duly charged and incarcerated, pending trial. A contaminated negative control should have rung alarm bells, but it was dismissed without any further action.

Five months later a contamination incident was confirmed by reanalysis of the original swabs and the individual was released. The consequence of the contamination incident was not just confined to a wrongful DNA match, as the error was compounded by: (a) misidentification of the body fluid or source of the DNA and (b) wrongful assumptions on the activity of sexual assault.

Scientists need to be extremely cautious if an assessment is made that goes beyond the simple fact of a DNA profile match. For example, the DNA statistic calculated for the strength of evidence of the DNA profile cannot simply be transposed to encompass the body fluid of origin and subsequently used to infer the activity that led to deposition. There is always some additional uncertainty to consider beforehand, which will always reduce the combined strength of evidence.

2.1.1 Background to the Contamination Event

New robotics had been installed at the laboratory. Validation studies had been carried out and the data assessed by the UK accreditation bodies NDU (National DNA Database Delivery Unit) and United Kingdom Accreditation Service (UKAS) and permission was duly given for the laboratory to begin processing using the new methodology.

2.1.2 The Crime Events: The First Incident

The first incident was a saliva sample submitted to the laboratory by police as the result of a “spitting incident” by the defendant (a relatively minor offence). The saliva sample was analyzed on 6 October and reported as a “match.” The reference DNA profile was uploaded to the national DNA database.

2.1.3 The Crime Events: The Second, Unrelated, Incident

The second incident was very serious. A woman was attacked and raped in Manchester on 2nd October, 2010. The exhibits for analysis consisted of two vulval swabs, two low vaginal swabs, two high vaginal swabs. Semen was detected on each of the swabs and separated from other cellular material by differential extractions, each fraction was analyzed for DNA.

2.1.4 Results of the Analysis

The analysis was carried out on 7th October. The low, high, and one vulval swab produced DNA profiles from the seminal fraction, identified as the victim’s boyfriend.

The other two vulval swabs gave a mixture from the seminal component containing the victim’s boyfriend and an unknown male with 17 alleles present (profile not available for review).

2.1.5 The Contamination Event

On 11th October, it was discovered that a stack of plastic trays removed as waste from one of the robotic units was incorrectly reused. This was reported internally as a quality incident. A number of samples were rerun as a result. The matter was not escalated, and the case which was the subject of the regulator’s report was processed on 7th October and was not identified as “at risk” by the processing laboratory.

Recommendation 2:

• If a negative control shows a partial, or full, DNA profile, then this indicates that the batch of samples concurrently processed may be compromised and should be completely rerun.

• There may be implications for the casework procedure in general and the source of the profile should be investigated by comparison with staff elimination databases, the national DNA database (NDNAD), and any other samples processed during a relevant period of time.

The DNA profile was submitted to the NDNAD on 17th October and a “match” with Adam Scott, the defendant, was made. There followed a report written by the forensic scientist which is reproduced in full below (taken directly from the regulator’s report; Rennison, 2012):

2.1.6 The Written Statement

Written Statement—Adam Scott

It is estimated that the chance of obtaining matching DNA components if the DNA came from someone else unrelated to Adam Scott is approximately one in one billion (one billion is one thousand million). In my opinion the DNA matching that of Adam Scott has most likely originated from semen.

Interpretation and conclusions:

The DNA detected in the sample recovered from (victim’s name) vulval swab (GE2b) can be accounted for by a mixture of DNA from (victim’s boyfriend) and Adam Scott. In my opinion these findings are what I would expect if Adam Scott had some form of sexual activity with (victim’s name). In order to assess the overall findings in this case I have therefore considered the following propositions:

• Adam Scott had vaginal intercourse with (victim’s name)

• Adam Scott has never been to Manchester and does not know (victim’s name)

In my opinion, the scientific findings in relation to (victim’s name) vulval swab provide strong scientific support for the view that Adam Scott had sexual intercourse with (victim’s name) rather than he did not. However, given the position of the semen matching Adam Scott and an absence of semen on (victim’s name) internal swabs, the findings do not specifically support vaginal penetration with ejaculation inside the vagina. They may also support vaginal-penile contact with external ejaculation or vaginal intercourse with no internal ejaculation.

2.1.7 Analysis of...