AC 1.3
● There are two types of evidence collected in criminal investigations:
○ physical evidence and testimonial evidence.
■ Physical evidence is real,and consists of tangible articles
● such as blood, DNA, hair, footprints or a weapon.
■ Testimonial evidence is a statement or spoken words from a
defendant, victim or witness.
● These can take the form of eyewitness accounts of victims
statements.
Physical evidence
● Physical evidence is a key part of prosecutions and court cases, with physical
evidence being present in almost every criminal case.
○ This could be due to Locard's Exchange Principle
■ which every time someone enters an environment, something is
added to and removed from it.
■ In other words, every contact leaves a trace.
● This applies to contact between individuals as well as between
and individual and the physical environment.
○ Scene of crime officers always work on the principle that physical evidence is
left behind at every crime scene
■ as a result of locard's exchange principle.
● this exchange can cause issues during criminal cases
○ Example : Barry George
■ where gunshot residue of one ten thousandth of
a centimetre was found in his jacket pocket,
● which led to Barry george being wrongly
imprisoned for murder.
■ This gunshot residue was said to have come from the police firearms
that were taken into his flat whilst being search
● due to locard's exchange principle,ended up inside his pocket
○ which led to a miscarriage of justice
● When dealing with an outdoor crime scene,however, physical evidence can become
problematic.
○ For example:
■ weather conditions may destroy and contaminate evidence, rendering
it useless in an investigation.
○ The evidence may simply be lost or destroyed by harsh weather conditions
such as rain or wind.
■ Outdoor crime scenes often attract media
● which could impact the reliability of the evidence due to
contamination
● These factors should be considered when testing the evidence
found.
, ○ To mitigate against these potential issues:
■ it is vital for the police to secure the crime scene by putting up
temporary structures
● ensure the scene is not contaminated by wearing bodysuits
● using stepping stools when collecting evidence.
● Once discovered, physical evidence must be handled in different ways.
○ For example:
■ When dealing with hair and fibre samples, a body suit must be worn to
collect evidence.
● Hairs are placed into dna tubes and sealed, whilst fibres are
collected using sticky tape
● being placed on a paper background before being put into an
evidence bag.
○ If possible, all hair and fibres should be collected as a larger sample allows
for more testing to be done.
■ Once collected, the labelled evidence bags get sent to the lab, kept
separate from each other
● avoid possible contamination.
■ Once at the lab, hair and fibres are analysed under a microscope
● may undergo a toxicology exam to look for drug use in hair.
■ Hair can tell the forensic scientist :
● the ethnicity of the person
● hair color
● if on drugs
● which part of the body the hair came from.
○ The hair must contain the root if DNA is to be found
■ In relation to fibres, different patterns and colors can be identified, as
well as the material of the fibre
● which may come in useful when identifying a victim.
● Another form of physical evidence is footprints, which can be found in two forms:
○ latent footprints (a 2D view)
○ patent footprints (3D footprint).
■ When collecting latent footprints, a lifting dust must be used, as well
as an electrostatic plate
● which attracts the dust particles to create the outline of the
footprint.
■ Patent footprints are collected different, with a cast of the print being
made from power and water.
● Once the mould has set, the footprint is boxed and sent to the
lab.
■ Footprint experts will then make a copy of the shoe onto plastic before
looking for shoes with the same pattern on the shoe database.
● Marks and specific cuts on the bottom of the shoe will also be
recorded
○ can be compared to an offender's shoe when arrested
○ Insoles of shoes may also be checked for a person's individual footprint,
● There are two types of evidence collected in criminal investigations:
○ physical evidence and testimonial evidence.
■ Physical evidence is real,and consists of tangible articles
● such as blood, DNA, hair, footprints or a weapon.
■ Testimonial evidence is a statement or spoken words from a
defendant, victim or witness.
● These can take the form of eyewitness accounts of victims
statements.
Physical evidence
● Physical evidence is a key part of prosecutions and court cases, with physical
evidence being present in almost every criminal case.
○ This could be due to Locard's Exchange Principle
■ which every time someone enters an environment, something is
added to and removed from it.
■ In other words, every contact leaves a trace.
● This applies to contact between individuals as well as between
and individual and the physical environment.
○ Scene of crime officers always work on the principle that physical evidence is
left behind at every crime scene
■ as a result of locard's exchange principle.
● this exchange can cause issues during criminal cases
○ Example : Barry George
■ where gunshot residue of one ten thousandth of
a centimetre was found in his jacket pocket,
● which led to Barry george being wrongly
imprisoned for murder.
■ This gunshot residue was said to have come from the police firearms
that were taken into his flat whilst being search
● due to locard's exchange principle,ended up inside his pocket
○ which led to a miscarriage of justice
● When dealing with an outdoor crime scene,however, physical evidence can become
problematic.
○ For example:
■ weather conditions may destroy and contaminate evidence, rendering
it useless in an investigation.
○ The evidence may simply be lost or destroyed by harsh weather conditions
such as rain or wind.
■ Outdoor crime scenes often attract media
● which could impact the reliability of the evidence due to
contamination
● These factors should be considered when testing the evidence
found.
, ○ To mitigate against these potential issues:
■ it is vital for the police to secure the crime scene by putting up
temporary structures
● ensure the scene is not contaminated by wearing bodysuits
● using stepping stools when collecting evidence.
● Once discovered, physical evidence must be handled in different ways.
○ For example:
■ When dealing with hair and fibre samples, a body suit must be worn to
collect evidence.
● Hairs are placed into dna tubes and sealed, whilst fibres are
collected using sticky tape
● being placed on a paper background before being put into an
evidence bag.
○ If possible, all hair and fibres should be collected as a larger sample allows
for more testing to be done.
■ Once collected, the labelled evidence bags get sent to the lab, kept
separate from each other
● avoid possible contamination.
■ Once at the lab, hair and fibres are analysed under a microscope
● may undergo a toxicology exam to look for drug use in hair.
■ Hair can tell the forensic scientist :
● the ethnicity of the person
● hair color
● if on drugs
● which part of the body the hair came from.
○ The hair must contain the root if DNA is to be found
■ In relation to fibres, different patterns and colors can be identified, as
well as the material of the fibre
● which may come in useful when identifying a victim.
● Another form of physical evidence is footprints, which can be found in two forms:
○ latent footprints (a 2D view)
○ patent footprints (3D footprint).
■ When collecting latent footprints, a lifting dust must be used, as well
as an electrostatic plate
● which attracts the dust particles to create the outline of the
footprint.
■ Patent footprints are collected different, with a cast of the print being
made from power and water.
● Once the mould has set, the footprint is boxed and sent to the
lab.
■ Footprint experts will then make a copy of the shoe onto plastic before
looking for shoes with the same pattern on the shoe database.
● Marks and specific cuts on the bottom of the shoe will also be
recorded
○ can be compared to an offender's shoe when arrested
○ Insoles of shoes may also be checked for a person's individual footprint,
