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dna project.co.za

Welcome. Please visit our website. www. dna project.co.za. or follow us on Facebook and Twitter. DNA Awareness Workshop. DNA Awareness Workshop. DNA Awareness Workshop. Aims of the workshop:.

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dna project.co.za

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  1. Welcome Please visit our website www.dnaproject.co.za or follow us on Facebook and Twitter

  2. DNA Awareness Workshop

  3. DNA Awareness Workshop

  4. DNA Awareness Workshop Aims of the workshop: • To provide an explanation of how DNA/ biological evidence can help to solve crimes. • The important role we play as a first responder in ensuring that a crime scene is properly secured and protected.

  5. DNA Awareness Workshop Workshop topics: • Types of crime and crime scenes • Types of evidence • Biological evidence and DNA Profiles • Crime scene preservation • Chain of custody

  6. Crimes and crime scenes What types of crimes occur in South Africa? • Murder • Burglary • Rape • Hijacking

  7. Crimes and crime scenes What is a crime scene? A crime scene is a place or body containing clues about who committed the crime. • Building • Car • Parking lot • Body • Home • Office

  8. Crimes and crime scenes Locard’s Principle: “every contact leaves a trace” Crime scene Victim Criminal

  9. Crime scenes: Types of evidence

  10. Crime scenes: Types of evidence BLOOD WEAPONS FINGERPRINTS CIGARETTE BUTT CLOTHING BOTTLE SHOE PRINTS SEMEN

  11. Types of evidence: Fingerprints Fingerprints can be used to uniquely identify a person

  12. Types of evidence: Sources of DNA

  13. Types of evidence: Biological (DNA) BLOOD HAIR Saliva Blood Skin cells Semen Hair Sweat CIGARETTE BUTT CLOTHING BOTTLE SEMEN

  14. DNA – deoxyribonucleic acid

  15. Biology 101

  16. What is DNA? Everyone’s DNA is different (except for identical twins) DNA contains the information that determines what we look like – it’s our “blueprint”

  17. What is DNA? DNA is found in all cells in our bodies (except red blood cells) The DNA in every cell of our bodies is identical

  18. DNA in forensic investigations Because the DNA of all people is different we can: • Identify or exclude a known suspect • Link a suspect, witness or victim and crime scene • Identify missing persons

  19. Contamination of DNA evidence • DNA evidence can easily become contaminated. • Contamination can occur when DNA from another source is mixed with the DNA evidence. • Heat, sunlight, moisture, bacteria and even mould may damage or affect the quality of the DNA evidence collected at a crime scene thereby rendering it useless to the police.

  20. Evidence collection kits

  21. Buccal swab

  22. DNA Profiles

  23. What is a DNA profile? A DNA profile is simply a unique list of numbers obtained from a person’s DNA. MARKER 11, 2 3, 14 8, 24 22, 10 21, 14 16, 7 11, 12 2, 3 23, 8 X Y LOCUS 10 markers are required to build a DNA profile in SA. The FSL does this by examining 10 regions (loci) in a person’s DNA. 9 markers will consist of a pair of numbers. The 10th marker will specify sex.

  24. Inheritance of chromosomes Mother 22 pairs XX Father 22 pairs XY Each nucleus within a cell contains 46 chromosomes (23 pairs) in total We inherit half from each parent sperm eggs 22 X 22 X 22 X 22 Y

  25. DNA profiling: How it works 4 different building blocks (A, C, G and T) • Non-functional DNA: • High proportion of sequence variation • Enough differences to make DNA unique

  26. DNA profiling: How it works Chr 11 ATCT ATCT ATCT ATCT ATCT ATCT ATCT Chr 11 ATCT ATCT ATCT ATCT ATCT Region (locus) on Chromosome 11 with repeated segments – short tandem repeats (STR) Extract DNA out of sample and amplify DNA segments (PCR) Separate and visualize DNA fragments using electrophoresis Store profile as Numbers 5/7

  27. Uses of DNA Profiling: Matching evidence to suspects Suspect 1 Suspect 2 Evidence Marker 1 Marker 2 Marker 3

  28. Crime Scene

  29. DNA profiles collected from evidence at the crime scene Evidence - Blood Evidence - Saliva 11, 7 2, 3 23, 8 7, 11 3, 17 8, 14 11, 14 2, 3 23, 22 X Y 10, 19 5, 18 23, 7 17, 11 13, 17 22, 23 9, 24 8, 2 21, 11 X X BLOOD CIGARETTE BUTT

  30. Matching evidence to suspects Suspect Crime scene evidence No match ✔ Match (Hit) Confirms suspect was at the crime scene Suspect innocent

  31. South Africa’s National DNA Database DNA profiles are kept on a National DNA Database • DNA profiles collected from crime scenes. • DNA profiles from certain suspects arrested for criminal offences.

  32. Legislation regulating the use of DNA evidence • Currently no specific legislation exists in SA. • Section 37 of the Criminal Procedure Act, 51 of 1977 is the only statutory provision that deals with ascertainment of bodily features of an accused. • The Criminal Law (Forensic Procedures) Amendment Bill B9B-2013 (“DNA Bill”) has been drafted to address the lack of legislation.

  33. The ‘DNA Bill’ • Crime Scene Index: DNA profiles obtained from biological evidence collected from crime scenes • Arrestee Index: DNA profiles taken from persons arrested for, or suspected of having committed, a Schedule 8 offence • Convicted Offender Index: DNA profiles of convicted offenders (Schedule 8 offences)

  34. The ‘DNA Bill’ • Investigative Index: DNA profiles from persons taken with informed consent or by warrant, if necessary, for the purpose of investigating an offence • Elimination Index: DNA profiles of people working in the collection and analysis of forensic samples • Missing persons & unidentified human remains Index: DNA profiles of missing persons and unidentified human remains

  35. Schedule 8 Offences • Murder • Culpable homicide • Rape or compelled rape • Sexual assault, compelled sexual assault or compelled self-sexual assault • Any sexual assault against a child or person who is mentally disabled • Trafficking in persons for sexual purposes • Robbery • Kidnapping • Arson

  36. Matching evidence to DNA database Crime scene evidence National DNA Database Match Match ✔ ✔ Person previously arrested or convicted Same criminal at many crime scenes

  37. What else can we learn from a DNA profile? Fingerprint DNA Profile 6, 9 17, 4 21, 19 3, 7 25, 11 ... hair colour? eye colour? height? weight? A DNA profile, like a fingerprint, reveals no personal information and is merely a unique identifier.

  38. How to be prepared when arriving at a crime scene • Good planning, organisation and co-ordination will ensure valuable forensic evidence will be preserved. • Arriving unprepared may result in missed opportunities. • Bad organisation can result in evidence being lost. • Having too many unqualified people involved at a crime scene runs the risk of contaminating or destroying important evidence.

  39. Crime scene preservation D •Don’t touch N •Note, record, observe A•Assist police officers C •Comfort and support victims S •Secure the crime scene I •Insist no one interferes

  40. D - Don’t touch • Nothing should be touched unless absolutely necessary. • Wear protective clothing if you absolutely have to enter the crime scene. • Use a single path when entering and leaving. • Do not use any facilities at the scene and avoid eating, drinking or smoking at the scene. • Avoid moving anything or anybody from the original location.

  41. N - Note, record, observe • Make notes with sketches and if need be take photos, video and/or measurements. • Note time of arrival. • Identify and note signs of any activities. • Note who is present, is seen leaving or has entered the scene.

  42. A - Assist police officers • Provide assistance by requesting witnesses to wait near the crime scene for an Investigating Officer. • Prevent non-essential people from entering the crime scene.

  43. C - Comfort and support victims • Offer comfort and aid at the crime scene without disturbing the crime scene. • Consider health and safety risks such as body fluids and broken glass. • Note: If there is a conflict between preservation of evidence and saving a life, priority is always given to emergency medical care.

  44. S - Secure the crime scene • Demarcate a larger area first than a smaller one. • Use a physical barrier to cordon off the scene. • Prevent non-essential people from entering. • Make a note if any non-essential people were in the cordoned off area before the barrier was erected.

  45. Crime scene management - SAPS Crime scene manager Crime scene expert Crime scene investigator

  46. I - Insist no one interferes • The crime scene may contain valuable evidence and the less people who enter the scene, the greater the chance of finding uncontaminated DNA evidence. • Access should ideally be limited to the CSI’s and medical personnel who are attending to the victims present at the scene.

  47. Chain of custody WEAKEST LINK IN THE CHAIN Crime committed Crime scene secured by first responding officer Suspect linked to crime scene Suspect 1: 14,15 17,18 23,24 Suspect 2: 15,18 17,19 23.2,24 Evidence: 15,18 17,19 23.2,24 DNA profiles compared Evidence collected by CSI DNA analysed at FSL

  48. Thank you Please visit our website www.dnaproject.co.za or follow us on Facebook and Twitter

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