98 Crime scene examination

Transcription

1 98 Crime scene examination by John Horswell Douglas Elliot BSc (Hons), PhD [Updating author, March 2012] 98-1

2 EXPERT EVIDENCE Author information Douglas Elliot obtained his Bachelor of Science degree in Biochemistry from the University of Edinburgh, Scotland, and his PhD, also in Biochemistry, from the Royal Free Hospital School of Medicine, University of London, England. Postdoctoral study at the University of London and the University of Auckland, New Zealand, followed. Dr Elliot then joined the Department of Scientific and Industrial Research, Auckland, later the Institute of Environmental Science and Research Ltd (ESR), as a forensic scientist. Initial specialities included crime scene examination, and forensic serology and molecular biology. Dr Elliot is at present a Science Leader in the Auckland Service Centre of ESR, carrying out crime scene examination and evidence collection duties for the New Zealand Police. He has given evidence in court on many occasions. Since 1997, Dr Elliot has been the Director of the Forensic Science Programme in the Department of Chemistry, University of Auckland, which offers postgraduate qualifications in forensic science to New Zealand and international students. Dr Elliot has been President of the New Zealand Forensic Science Society. Dr Elliot may be contacted at: Director Forensic Service Centre ESR Private Bag Mt Albert AUCKLAND NEW ZEALAND Telephone: Web: [email protected] 98-2 Expert Evidence

3 TABLE OF CONTENTS INTRODUCTION... [98.10] WHAT IS A CRIME SCENE EXAMINER?... [98.50] EDUCATION AND TRAINING OF CRIME SCENE EXAMINERS... [98.90] THE PURPOSE OF CRIME SCENE EXAMINATION... [98.130] PRINCIPLES OF CRIME SCENE EXAMINATION... [98.170] THE PRELIMINARY PROCEDURES OF A CRIME SCENE EXAMINATION Control of the scene... [98.210] Assessment and preparation prior to attending the crime scene... [98.220] Securing the crime scene... [98.240] ENTERING THE CRIME SCENE... [98.250] GENERAL SURVEY OF THE CRIME SCENE... [98.290] CRIME SCENE PHOTOGRAPHY... [98.330] CRIME SCENE SKETCHING AND SCALE DRAWINGS... [98.370] SPECIFIC EXAMINATION OF THE CRIME SCENE... [98.410] Item examination... [98.420] COLLECTION TECHNIQUES... [98.460] Hand-picking... [98.470] Tape-lifting... [98.480] Sweeping... [98.490] Vacuuming... [98.500] Swabbing... [98.510] Direct sampling... [98.520] The collection sequence... [98.530] Comparison samples... [98.540] Packaging and sealing... [98.550] Infested material... [98.560] Labelling... [98.570] Preservation... [98.580] HEALTH AND SAFETY CONSIDERATIONS AT A CRIME SCENE... [98.620] WHERE DOES THE CRIME SCENE EXAMINER S ROLE END AND THE LABORATORY SCIENTIST S ROLE BEGIN?... [98.660] CONCLUSION... [98.700] Item collection kit... [98.740] Use of special collection instruments... [98.760] Collection techniques for commonly encountered types of physical evidence... [98.780] Figures... [98.840] [The next text page is 98-51] 98-3

4 EXPERT EVIDENCE 98-4 Expert Evidence

5 INTRODUCTION [98.10] This chapter examines the philosophy underlying credible crime scene examination, the duties of a crime scene examiner, the attributes which make a successful crime scene examiner, the appropriate education and training for crime scene examiners, and the mechanics of the actual crime scene examination. The success or failure of laboratory examinations depends on the following: (1) the receipt of all relevant potential evidence; (2) the preservation of any potential evidence; and (3) the ability to establish proof of origin and the integrity of items submitted during the course of the investigation. Crime scene examination is the function of Searching, Recording and Retrieving relevant evidentiary material. The crime scene examiner is concerned with physical things or items, and the investigator is concerned with people involved in criminal matters. The use of the term crime scene investigator or crime scene investigation, often abbreviated to CSI, has gained traction and wide usage due to the popular television series. In these programmes the crime scene examiners act as investigators according to the above definition. This rarely occurs in real life. The concept of a dual investigation, of people and physical evidence, is by no means new, as Paul Kirk stated (1974, p 1): A balanced approach to criminal investigation must be dual, it must concern itself both with people and things. The police investigator is the case manager or is otherwise involved at a high level in the co-ordination and organisation of the investigation of the scene. The crime scene examiner is the site or scene examiner and finder of potential evidence. The laboratory worker is the examiner of the potential evidence. All three look at possibilities (hypotheses) and test those possibilities against known facts. Some examination of potential evidence, may however, take place at the scene. A stain may be tested to determine whether or not it is a particular body fluid, the result of this test determining whether or not it is collected as potential evidence and transferred to the laboratory. Crime scene examination must be carried out in a methodical, objective and independent way by applying scientific methodology in exactly the same way as the laboratory worker examines submitted items. There is a fundamental similarity between the forensic examination and collection of potential evidence of a scene, and the forensic examination and collection of potential evidence of an item in the laboratory. In Australasia, as in the rest of the world, different jurisdictions operate slightly different systems of crime scene examination: the various systems are discussed below. For example: (1) police (sworn or non-sworn) scenes of crime officers attending volume crime and 98-51

6 [98.10] EXPERT EVIDENCE serious crime scenes in Australasia, some parts of the United Kingdom and North America; (2) civilian scientists attending serious crime scenes in Victoria, Australia; (3) civilian scenes of crime officers in the United Kingdom; (4) scientists from the laboratory in some jurisdictions in the United Kingdom, Australia and North America; (5) detectives supported by specialists from police resources and scientists from the Institute of Environmental and Forensic Science in New Zealand; and (6) detectives undertaking the full examination of crime scenes, for instance, fire marshals with the New York City Fire Department. This wide range of models is largely due to the way forensic science organisations have grown, which has tended to be in response to demands for increased or expanded services, rather than in a controlled or planned way. The range of models also means that jurisdictions have found their own ways of dealing with the demands of crime scenes, and the linking of work done at scenes to subsequent laboratory analyses. It is therefore impossible to draw up a specific best practice for crime scene management and examination. However, some general comments can be made. Crime scenes vary in size and complexity, ranging for example from a simple burglary where minimal reconstruction is required, to a homicide with one or more victims and one or more offenders. It may therefore be that the skills required of a crime scene examiner differ from scene to scene, and that more than one examiner can attend a scene, depending on their differing skill sets. Different jurisdictions can divide the various roles or skills among different people. What is important is that the police as primary investigators can call on the skills as required for any particular scene. These skills could include forensic pathology, forensic entomology, impression (fingerprint, shoeprint, toolmark) collection and enhancement, bloodstain pattern analysis, the identification of body fluids, forensic photography and forensic ballistics. A number of people may therefore be part of the examination and processing of the scene. Areas of the UK have chosen to train detectives as Crime Scene Co-ordinators or Crime Scene managers. Their role is to call to the scene the examiners with the required skills, and so they require knowledge of the scientific skills that may be required, and how the examining specialists may be most efficiently deployed. This role has been trialed in NZ. A distinction is sometimes drawn between a scientist attending a scene and a police crime scene examiner. Provided appropriate training has been given in the investigation of a crime scene, both types of examiner should be able to assist the investigating officer. The scientist may have an advantage in that he or she should be trained in the framing of hypotheses and should have an in-depth knowledge of the scientific principles of the tests and analyses carried out. The police crime scene examiner may have an advantage in recording the scene from the police perspective, and being able to act as an officer-in-charge of the scene. If we define a scientist as a person with a bachelor s degree or similar in a natural or physical science, then it can be seen that there is no reason why a police scene examiner need not also be a scientist. The combination of the civilianisation of crime scene workers (as seen in the UK and in NZ) with the increase in popularity of university and other courses delivering tertiary forensic science qualifications is increasing the number of sworn and non-sworn police staff who could describe themselves as scientists who also attend crime scenes. It is important to emphasise that the overall control of the crime scene is with the investigating police officers, at whichever level this authority has been vested, and that a specialist who Expert Evidence

7 INTRODUCTION [98.10] attends the crime scene needs to communicate with the investigating officers and with other scene examiners to optimise the scene examination and to minimise any conflict over process and priority. Accredited laboratories may have particular educational requirements relating to their scene-going and other staff. The key to success here is education, experience and training on all sides so that everyone knows where their contribution begins and ends. The training of crime scene examiners is considered at length below, [98.90]. [The next text page is ] 98-53