1. Year 10 Forensic Science
What is Forensic Science?
Hazards and Protection
Collecting Evidence
2. Learning intention/goals
To understand what Forensic Science is
To understand the roles of Forensic Scientists
To understand the hazards and risks associated with Forensic
Science
To become familiar with the integrity of collecting evidence
Success criteria
I understand what Forensic Science is
I understand the roles of Forensic Scientists
I understand the hazards and risks associated with Forensic Science
I am familiar with the integrity of collecting evidence
3. WHAT IS FORENSIC SCIENCE?
•the application of a science to answer questions of interest to a crime.
•comes from the Latin forensis, meaning "of or before the forum."
•In Roman times, a criminal charge would be presented before the public in the
forum. Both the person accused and the accuser would give speeches. The
individual with the best argument would determine the outcome of the case
4. •aka “The French Sherlock
Holmes”
•formulated the basic
principles of forensic science
•“Every contact leaves a
trace”
•Started the first police
laboratory in Lyon in 1910
Edmond Locard
(1877 – 1966)
5. Research ~ Hazards
In pairs or using your BYOD, complete the following. You have 2 mins
on the timer
1. What do these initials mean:
• HSE
• PPE
• COSHH
2. Complete the following:
– A hazard is
– A risk is
3. What is meant by sharps?
Health and Safety Executive
Personal Protection equipment
Control of Substances Hazardous to Health
Anything that might cause harm.
The chance that someone could be harmed.
Any sharp instrument or object.
6. Method of
entry into the
body
inhalation
skin absorption
ingestion
injection
Nature of hazard
contaminants that
make contact with
the skin
contaminants such
as sharp objects that
can puncture the
skin
airborne e.g. dusts,
smoke, vapours,
gases
contaminants that
are able to enter the
mouth
Action to reduce the
risk
wash hands before eating or
smoking. Do not bring food into
unsuitable areas.
Use equipment such as safety
glasses, gloves and other protective
clothing
Exercise caution when handling.
Wear gloves at all times. Dispose
of sharp objects in special
containers.
Ventilation and/or respiratory
protection masks.
7. Protective clothing
Face mask
Protects against inhaled
particles and prevents
contamination from the
officer’s saliva.
Goggles
Protect eyes from
chemical hazards.
Hooded Plastic Suit
Protects the officer at
the scene and prevents
contamination of the
scene.
Gloves
Protect from materials
absorbed through the
skin, prevents
contamination by
fingerprints and DNA.
Shoe covers
Prevent footprints
from damaging
evidence.
Complete the task in your
booklet on protective
clothing.
8. Roles
Detective (D)
Senior Investigating Officer (SIO)
Scenes of Crime Officer (SOCO)
Senior Scenes of Crime Officer (SSOCO)
Scene Guard
To question suspects and investigate lines
of enquiries.
To co-ordinate the overall investigation
To record and recover valid evidence at crime scene .
To manage the forensic examination of the scene.
(SG) To preserve the scene and to make
sure no unauthorised persons enter the scene.
10. Processing a Crime Scene
Valid Evidence
Valid evidence is based on the truth. It can be accepted in court.
Forensic scientists use two procedures to make sure evidence is
valid:
• Avoid contamination
•Record accurately
11. Contamination
Definition:
The unwanted transfer of material which must be avoided
at a crime scene
Individuals can contaminate the scene or evidence at any time
by:
• Leaving fingerprints / hairs / fibres / DNA
• Not sealing the evidence properly
• Putting more than one piece of evidence in a bag at once
• Using old equipment
Contaminated evidence can not be used in a court of law and
may result in criminals being set free.
12. Establishing Evidence
You will need to find out:
• How contamination of the crime scene is prevented
• How the officers protect themselves from harm
• What photos and measurement were taken
• What evidence is collected, and how it is stored.
• What can be learned from the evidence?
Protecting the evidence at the Crime scene
Look at the next slides and determine the measures that
have been put in place to protect the validity of the
evidence.
13. Picture A ~ Cars
Tape used to created a cordoned off
area to prevent people from entering
the scene unauthorised.
Police officers used to prevent
unauthorised people entering the area.
14. Picture B ~ Scene of Crime Officer (SOCO) at
work
Tent
Provides screen and
distinct barrier
Suits
SOCOs gathering
evidence correctly
dressed. NB. Any Police
Detective entering the
scene would be required
to wear a protective suit.
BUT they don’t on
TV do they?
Stepping Plates
Provide a safe and
secure way of
approaching the
scene.
15. Picture C ~ On the ground and around
Tent
Provides screen and
distinct barrier
Crime Scene Tape
Creates an inner
cordon.
Full protective
clothing!
Evidence markers.
16. Processing a Crime Scene
Correct processing of a crime scene is essential to gather as much
information as possible and prevent contamination.
STEP 1
INTERVIEW - The SOCO arrives on the scene and makes sure it is secure.
An initial walk-through is conducted to get a feel for the crime
scene.
The first officer at the scene and/or the victim is interviewed to
ascertain the "theory" of the case; what allegedly happened, what
crime took place, how was the crime committed etc. This information
may not be 100% factual but it will give the SOCO a place to start
from.
The SOCO also needs to find out if anything has been moved. Potential
evidence is noted but at this point, nothing is touched.
17. Processing a Crime Scene
STEP 2
DOCUMENTATION – Is the "theory" of the case supported by what the
SOCO observes? Examine the scene to identify evidence, point of
entry and exit, the general layout, etc.
The SOCO thoroughly documents the scene as well as any potential
evidence by taking photographs and drawing sketches during a
second walk-through. Sometimes, a video walk-through may be
conducted. Again, nothing is touched.
18. Processing a Crime Scene
STEP 3
PROCESSING - Now it's time to touch stuff -- very, very carefully. The
SOCO systematically collects all potential evidence, tagging it,
logging it and packaging it so it remains intact for further analysis
by a crime laboratory.
The lab processes all of the evidence collected at the crime scene.
When the lab results are in, they go to the lead detective on the
case.
19. It is essential that any items of physical
evidence can be traced from the:
crime scene → lab → lab report → courtroom
This is known as maintaining the chain of
custody or continuity of evidence. If the chain
is broken, the forensic investigation may be
fatally compromised.
Processing a Crime Scene
20. Search Patterns
There are several search patterns available for a SOCO to
choose from to assure complete coverage and the most
efficient use of resources.
21. Search Patterns
1) Inner Spiral
The SOCO starts at the perimeter
of the scene and works toward the
centre.
2) Outer Spiral
The SOCO starts at the centre
of scene (or at the body) and
works outward.
Spiral patterns are good if there is only one SOCO at the scene.
22. Search Patterns
3) Parallel
The SOCO team form a line and
walk in a straight line, at the same
speed, from one end of crime
scene to the other.
4) Grid
Two parallel searches, offset by
90 degrees, performed one
after the other.
23. Search Patterns
5) Zone
The lead SOCO divides the crime scene into sectors,
and each team member takes one sector. Team
members may then switch sectors and search again
to ensure complete coverage.
24. TASK
Read the Allison Bayden –Clay murder case and decide which search
patterns were employed to gather evidence and why.
• Quadrant search (Zone)
• Link Method
• Strip or line search (Parallel)
• Grid
• Spiral Search (inner and outer)
You will need to include a diagram of the SOCOs pathway through the
crime scene.
Also include any advantages and disadvantages of the search patterns.
In your opinion, which would be the most ideal search pattern?
25. Trace evidence (gunshot residue, paint residue, broken glass, unknown
chemicals, drugs, poison)
Impressions (fingerprints, footprints, tool marks)
Body fluids (blood, semen, saliva, vomit)
Hair and fibres
Soil and insects
Weapons and firearms evidence (knives, guns, bullet holes, cartridge casings)
Documents (diaries, suicide note, phone books; also includes electronic
documents like answering machines, text messages)
In General:- What kind of evidence
might a SOCO be searching for?
26. Video: Forensic Science used to solve
real crime scenes
• https://www.youtube.com/watch?v=1B6oOOl
GT2M&list=PL89QP7ZwONKmVLlYwPyf6aI-
wIrQjbnqX
27. Review: In your Booklets
• Name 3 different occupations related to
Forensic Science and briefly describe their role
..........................................................
• Valid evidence is dependent upon two things.
Name them ............
• Forensic Science is the ..............................
