forensics lecture 1- introduction

Question 1

what is forensic science?

Answer 1

the application of scientific methods and techniques to matters under investigation by a court of law.

Question 2

what is forensis?

Answer 2

in open court, public, from forum

Question 3

what is the role of the forensic scientist?

Answer 3

-the recovery snd continuity of evidence
-analysis of evidence
-presentation of scientific findings in court

Question 4

when are forensic scientists required?

Answer 4

-has a crime been committed?
-who is responsible?
-if the person responsible is traced, is there enough evidence to charge the person and support prosecution

Question 5

what are the dates for the history of forensic science?

Answer 5

6th century = finger prints used for ID in china
8th century = first example accepted as evidence
1835 = first bullet comparison
1836 = first forensic toxicology
1901 = ABO blood groups discovered
1904 = locard’s exchange principle
1986 = Alec Jeffreys DNA profiling

Question 6

what is forensic science like in England and Wales?

Answer 6

-Departments within police service
-Also private companies (e.g. Cellmark, LGC Forensics) and small scale practitioners

Question 7

what is forensic science like in Scotland?

Answer 7

Scottish Police Authority (Ireland - FSNI)
for crime scenes, fingerprint, most lab-based forensic science

Question 8

what is a forensic science regulator?

Answer 8

Currently Mr Gary Pugh
Ensures provisions of forensic science services are subject to appropriate quality standards

Question 9

what is the locards principle?

Answer 9

every contact leaves a trace

Question 10

what is physical fit?

Answer 10

Physical fit can prove beyond reasonable doubt the connection between a crime scene and a suspect

Question 11

what is a trace?

Answer 11

a mark left by something; minute (tiny) amount

Question 12

what is trace evidence?

Answer 12

very small amounts of material
Provide link
Locard’s Principle

Question 13

how do you recover evidence?

Answer 13

-Shaking
-Brushing
-Taping
-Vacuuming
-Swabbing
-Hand Picking
-Extracting
-pipette/Swab

Question 14

how do you target potential traces?

Answer 14

-Amount of material
-Persistence of material
-Finding the material
-Evidence value of the material

Question 15

what are fibres?

Answer 15

any long thin flexible solid object with a high length to transverse cross-section area ratio

Question 16

how does fibre analysis?

Answer 16

-Tapings
-Microscopy
-Thin Layer Chromatography
-Infrared spectroscopy

Question 17

what is the test for semen?

Answer 17

-Microscopy
-Acid Phosphatase *
N-napthyl phosphate + ortho-dianisidine

-p30
-Semen is a good source of DNA
-Seminal fluid – sterile (no sperm)

Question 17

what is the test for saliva?

Answer 17

Starch/Iodine

Salivary Amylase
Saliva may contain bacterial/cheek cells

Question 18

what can hair analysis determine?

Answer 18

the classification such as Human/animal, Body area, Race, Artificial alteration, Damage

Question 19

what are the parts of the hair?

Answer 19

the medulla in the centre, the Cortex in the middle and. surrounded by the cortex

Question 20

what are the points to note about blood testing?

Answer 20

-Not entirely specific
-False reactions
-Obvious stains
-Haemoglobin enzyme/catalyst
-Red blood cells and platelets have no DNA

Question 21

read the image for the screenshot of blood testing

Question 22

what is the test for blood pattern analysis?

Answer 22

-To provide information regarding the sequence of events:
-Position of the victim
-Evidence of struggle
-Provide evidence to corroborate or refute statements made by those involved:
-Stain patterns on suspect’s clothing
-Stain patterns on victim/at scene

Question 23

what are the types of blood pattern analysis?

Answer 23

passive, transfer, active

Question 24

what is passive patterns?

Answer 24

due to gravity=
Drops, Drips, Pools, Clots, Shape affected by target surface texture

Question 25

what is transfer patterns?

Answer 25

Wet bloody surface in contact with another surface produces a pattern=
Contact, Swipe/smear, Wipe, Smudge

Question 26

what is projected?

Answer 26

-Arterial spurt/gush
-Cast off stains

Impact
low, medium, high velocity

Point of convergence is the centre point

Question 27

what is glass analysis?

Answer 27

-Colour & Thickness
-Physical analysis
-Chemical analysis
– Scanning Electron Microspcope (SEM) & Energy Dispersive x-ray analysis

Information from crater shaped holes indicates direction of impact.

Question 28

how do assess the significance of trace evidence?

Answer 28

-Extent of comparison
-Rarity of trace material
-Expectations
-Combination of evidence
-Alternative, innocent sources
-Contamination

Question 29

how do you assess the reliability of trace evidence?

Answer 29

-Reputable
-Relevant circumstances
-Funding

Question 30

what is the area of chemistry in forensics analysis?

Answer 30

-Footwear, tool mark and tyre analysis
-Paint and glass analysis
-Explosives analysis

Question 31

what is the area of biology in forensics analysis?

Answer 31

-Blood, semen, other body fluids
-Hairs and fibres
-Blood pattern analysis
-DNA profiling

Question 32

what is the area of documents in forensics analysis?

Answer 32

-Any item with writing
-Inceptive analysis
-Evidential

Question 33

what is the area of toxicology in forensics analysis?

Answer 33

-Drugs or alcohol content in blood and urine samples in driving offences
-Presence of drugs in organs and tissues
-Identification of illegal drugs and their purity