What is evidence - lecture.pdf

What is evidence? Methods of Laboratory Examination Forensic Perspectives Dr Ana Andrade – [email protected] derby.ac.uk Sensitivity: I...

What is evidence? Methods of Laboratory Examination Forensic Perspectives Dr Ana Andrade – [email protected] derby.ac.uk Sensitivity: Internal  Body Title Text Arial Bold 32pt Lecture content Body Copy Arial 24pt What is Evidence? Types Analysis and scene considerations Transfer and persistence Contamination derby.ac.uk Sensitivity: Internal  Learning outcomes By the end of this session, you should be able to: Define what is evidence and evaluate their value Outline the different types of evidence Enumerate the different steps involved in the analysis of a trace Summarize the basics of trace transfer and persistence Analyze the main causes for trace contamination derby.ac.uk Sensitivity: Internal  What the word “evidence” mean? Please go to the following link and answer the poll! PollEv.com/anaandrade derby.ac.uk Sensitivity: Internal  derby.ac.uk Sensitivity: Internal  What does the word `evidence` mean? “..an outward sign..” – e.g. indication “..something that furnishes proof..” – e.g. testimony derby.ac.uk Sensitivity: Internal  Evidence What is Evidence? “..information etc. that gives grounds for belief used in a court of law..” make a fact or proposition more or less likely can exist in ‘isolation’ or in ‘combinations’ Combinations give more weight to an argument derby.ac.uk Photo by cottonbro from Pexels Sensitivity: Internal  Types of evidence Broadly classified into 3 types: Photo by Faruk Tokluoğlu from Pexels Photo by cottonbro from Pexels derby.ac.uk Sensitivity: Internal  Types of evidence Broadly classified into 3 types: Physical Evidence Photo by Faruk Tokluoğlu from Pexels Oral Evidence Photo by cottonbro from Pexels Documentary Evidence derby.ac.uk Sensitivity: Internal  Evidence Oral Evidence This is evidence which is verbally presented to the court or presented in the form of a witness statement that is read out in court Eyewitness (factual based evidence ONLY) Professional Witness e.g. Police Officer (mainly factual but can allow some opinion-based evidence) Expert Witness e.g., Forensic Scientist (FACTUAL and OPINION based evidence) derby.ac.uk Sensitivity: Internal Photo by cottonbro from Pexels  Evidence Physical evidence (Real Evidence ) - Trace Any object produced for the court that is not a document Macro trace Trace evidence Weapons Paint Drugs Glass fragments Vehicles etc. Fibres etc. Photo by Immo Wegmann on Unsplash derby.ac.uk Sensitivity: Internal  Evidence Documentary Evidence These are documents produced for the court containing information relevant to the case Statements taken from a witness Photographs Hard copy computer downloads Reports, images, directories, audit trails Supplementary material Fact sheets, maps, plans etc. derby.ac.uk Photo by Mohammad Danish from Pexels Sensitivity: Internal  Trace - Physical Evidence Most often found at volume crime scenes Burglaries Vehicle Crime etc. Can you give me examples of physical evidence found in Crime Scenes? derby.ac.uk Sensitivity: Internal  Trace – physical evidence that can be found on Crime Scenes It can be anything that potentially can give you information about the crime derby.ac.uk Sensitivity: Internal Foto de Faruk Tokluoğlu no Pexels  To determine if an object is an evidence you need to analyse the context derby.ac.uk Sensitivity: Internal  Strength of Evidence Type, Amount, Quality as well as the context of the scene ultimately dictates how strong a piece of evidence is Dictates what can be determined and interpreted derby.ac.uk Sensitivity: Internal  Relationships and Context Relationships between people, places and objects involved in crimes are critical to deciding what to examine and how to interpret the results Relevance of transferred evidence is variable and dependent upon relationship of victim and criminal derby.ac.uk Sensitivity: Internal  Relationships and Context Coincidental association When 2 objects, which have never been in contact with each other, have items on them which are analytically indistinguishable Important to establish context of the crime and those involved Helps to determine what evidence is significant Identifies most effective methods for collection or analysis Avoid indiscriminate collection derby.ac.uk Sensitivity: Internal  Relationships and Context Victim and Suspect only interact Victim and Suspect interact at a scene unfamiliar to both at a scene familiar to both e.g. Sexual assault in an field e.g. Suspect kills co-habiting victim at home Victim and Suspect interact Victim and Suspect interact at a scene only familiar to suspect at a scene only familiar to Victim e.g. Kidnap and assault in Suspects Vehicle e.g. Home burglary with an assault Victim Suspect Scene derby.ac.uk Sensitivity: Internal  Transferred items constitute ‘evidence’ according to Edmond Locard ‘Every contact leaves a trace’ Trace and Minute amounts of materials that are present at the location Contact of interest Evidence As a result of transfer between individuals between individuals and a location derby.ac.uk Sensitivity: Internal  Trace and Contact Evidence Hair Challenge Blood Fibres Saliva Context Glass Semen Where? Paint derby.ac.uk Sensitivity: Internal  Basis of Evidence: Transfer and Persistence Edmond Locard’s Exchange Principle - Edmund Locard (1877 - 1966) whenever two objects come in contact, a transfer of material occurs “…every contact leave a trace….” “it is impossible for a criminal to act, especially considering the intensity of a crime, without leaving traces of this presence”. when a perpetrator commits a crime they leave a trace of themselves at the scene while simultaneously taking something from the scene when they leave derby.ac.uk Sensitivity: Internal  Basis of Evidence: Transfer and Persistence A number of conditions affect the amount of evidence (material) that is transferred Ease with which material is lost (Shedability) Number of contacts Surface area of contact Pressure What form the material takes derby.ac.uk Sensitivity: Internal  Basis of Evidence: Transfer Transfer has different levels depending on the number of intermediaries between source and final location Consider these transfer scenarios: A B Primary transfer DIRECT transfer A B C Secondary transfer A B C D Tertiary transfer INDIRECT transfer A B C D E Quaternary transfer derby.ac.uk Sensitivity: Internal  Basis of Evidence: Persistence Persistence is a measure of the duration in which evidence remains in a location before it is either further transferred, degraded or collected as evidence Depends on a number of conditions: Type of evidence Location Environment Time interval between transfer and collection Activity around the evidence location derby.ac.uk Sensitivity: Internal  Once activity surrounding a scene has stopped, further transfer of material can be Evidence: regarded as contamination Contaminatio Cotamination = Undesired transfer of information from one source to another n Edmond Locard’s principle '…every contact leaves a trace…' Equally applicable for contamination Take every possible step to minimise contamination / cross contamination derby.ac.uk Sensitivity: Internal  Evidence: Contamination Wherever possible every item of evidence should be packaged separately Unless there is a clear association Work to robust standardized protocols in properly designed facilities Wear protective clothing and quality- centered protocols regarding handling and packaging of evidence derby.ac.uk Sensitivity: Internal  derby.ac.uk Sensitivity: Internal This Photo by Unknown Author is licensed under CC BY  Evidence: Observation and Recording Your eyes are one of your most important assets for this course. Never rush in !!!! üStand back with hands in pockets & THINK about what you are going to do. derby.ac.uk Sensitivity: Internal Foto de Alex Green no Pexels  Evidence: Observation and Recording Full Personal Protective equipment (PPE) üScene suit/lab coat, gloves, face mask, hair net, overshoes etc. Laboratory examinations: üClean the bench & lay down paper üSet out examination tools Dissection kit, pens, paper, measure etc. üNever break the original seal!! üOpen each exhibit away from the seal (opposite end) üHandle minimally/with care so as not to destroy other potential evidence types derby.ac.uk Sensitivity: Internal  Evidence: Observation and Recording Use only metric units of measurement and be consistent e.g. 23cm x 46cm or 230mm x 460mm Use pens, not pencils - why? Keep colour to a bare minimum!!!!! Black, red, green derby.ac.uk Foto de cottonbro no Pexels Sensitivity: Internal  Evidence: Observation and Recording Only require a sketch Not a masterpiece! derby.ac.uk Sensitivity: Internal  Analysis of Evidence In the routine scientific analysis of evidence, many factors exist that affect how evidence is analyzed: Detection Preservation Protect the integrity of the evidence Sampling Methods of analysis and examination strategy Equipment Calibration and LOD’s Reports Turnaround time Chain of custody (evidence continuity) derby.ac.uk Foto de Chokniti Khongchum no Pexels Sensitivity: Internal  Evidence - Analysis Two fundamental processes in the analysis of evidence: Identification Comparison Identification is the process of defining physical and chemical characteristics into successively smaller classes Natural Fibre Natural Polymer Man-made Polyamide Synthetic Polyester Polyester Polyurethane derby.ac.uk Sensitivity: Internal  Evidence - Analysis Comparison is the process of establishing the source of evidence Questioned evidence is compared with objects from a known source Determine whether or not sufficient common physical and/or chemical characteristics exist between both samples Strength of association depends on a number of factors: ü Kind of evidence ü Intra- and inter-sample variation ü Amount of evidence ü Location of the evidence ü Transfer and cross transfer ü Number of different kinds of evidence associated to one or more sources derby.ac.uk Sensitivity: Internal  Comparison of evidence Association Relationship between one or more items of evidence and a source Individualization One unique characteristic is found to exist in both the know How to prove that two materials are the same? derby.ac.uk Sensitivity: Internal This Photo by Unknown Author is licensed under CC BY  Evidence - Analysis Individualization occurs when at least one unique characteristic is found to exist in both the known and questioned samples Individualization is not identification alone derby.ac.uk Sensitivity: Internal  Continuity of Evidence Chronological documentation (paper trail), showing the seizure, custody, control, transfer, analysis, and disposal of the evidence Provides an audit trail Exists for each piece of evidence Demonstrates evidence integrity Avoid later allegations of tampering or misconduct which can compromise the evidence and/or case. What is involved? derby.ac.uk Sensitivity: Internal  Continuity of Evidence - packaging Each piece of evidence is individually packaged Sharpes Tubes Tamper Evident bags Paper sacks (TE Bags) Nylon bags (Volatiles) derby.ac.uk Sensitivity: Internal  AFBA/01 Continuity of Evidence - packaging 1 X STRAWBERRY DUREX plus WRAPPER Each piece of evidence is inscribed Custody labels 08:35 25/07/20 Directly on TE bag FRONT RECEPTION TE label + security seal UoDERBY Each label must contain ANA F B ANDRADE ID Number (exhibit No.) Seized by Ana Andrade Description Case number Date, Time and Location Print and signature KR-EXPL3 Where is was seized derby.ac.uk Sensitivity: Internal  Continuity of Evidence - packaging Package must only be opened away from the original seal and re-sealed after examination Each time the package is opened it must be recorded in the continuity section of the label üName, signature, date Minimum number of people handling the evidence Evidence is stored in a secure area when not being examined Failure to comply will render the item inadmissible in court derby.ac.uk Sensitivity: Internal  Chain of Custody A process that tracks the movement of evidence through its collection, safeguarding, and analysis lifecycle by documenting each person who handled the evidence, the date/time it was collected or transferred, and the purpose for the transfer. Is a list of places where the evidence was and people who were in possession of that evidence. This is an uninterrupted series of identified individuals, each of whom can be asked to testify that the integrity of the item of evidence was not compromised while it was in his or her safe-keeping. derby.ac.uk Sensitivity: Internal  In this session… - Types of evidence - Macro and trace evidence - Strength of evidence - Relationship and context - Evidence transfer and persistence - Evidence contamination - Evidence observation and recording - Analysis of evidence - Continuity of Evidence derby.ac.uk Sensitivity: Internal  Activities to engage before your first practical session derby.ac.uk Sensitivity: Internal  Activities to engage before your first practical session derby.ac.uk Sensitivity: Internal  Activities to engage before your first practical session derby.ac.uk Sensitivity: Internal  Activities to engage before your first practical session derby.ac.uk Sensitivity: Internal  Chapter 3 Chapter 1, sections 1.1 and 1.2 Fundamentals of Forensic Science Forensic Science HoucK, M & Siegal, J (2010) Jackson and Jackson derby.ac.uk Sensitivity: Internal  University of Derby, Kedleston Road, Derby, DE22 1GB T +44 (0)1332 591044 E [email protected] Any questions? derby.ac.uk Sensitivity: Internal