AC1.3 Explain how evidence is processed
Types of Evidence
Evidence can be divided into two categories:
Physical: also referred to as real evidence, consists of tangible articles such as hairs,
fibres, fingerprints and biological material.
Testimonial: statements or the spoken word from the defendant, a victim or
witness.
Physical evidence
The concept known as Locard's exchange principle states that every time someone enters
an environment, something is added to and removed from it. This principle is sometimes
expressed as 'every contact leaves a trace’ and applies to contact between individuals as
well as between an individual and physical environment. Scenes of crime officers always
work on the principle that physical evidence is left behind at every crime scene.
Testimonial evidence
Testimonial evidence is the spoken word of the witness, which could include either the
victim or defendant. Evidence must be admissible, which means complying with the rules of
evidence. For instance, in the Colin Stagg case, all the evidence relating to 'Lizzie' was
excluded by the trial judge.
Statements of witnesses will have been taken by each side and disclosed before the court
case. In court, testimonial evidence is usually given in the witness box with the opportunity
for the opposing side to cross-examine or question the witnesses' evidence.
Process of physical evidence collection
Bloodstains can be collected on sterile material, if still in a liquid form, and left to dry
at room temperature. Within 28 hours, they should be transferred to the laboratory
for the forensic scientists to examine. If the blood has already dried on material, the
article should be placed in a container, sealed and labelled.
Semen stains are often found on clothing or bedding and should be allowed to dry
on the material, then wrapped in paper and placed in paper bags. It is crucial in
offences of a sexual nature that evidence is secured and that a doctor examines the
victim. All appropriate clothing and other exhibits should be packaged separately.
Hair samples are likely to be on the clothing. If so, the clothing should be wrapped in
paper and submitted to the laboratory for examination. Any small fragments of hair
should be placed in the paper, which can be marked and sealed. Occasionally, the
analysis of hairs can reveal the possible race of the individual from whom they came
and the part of the body from which they originated.
Fibres and threads are often found on other items or caught in torn materials. An
examination can usually be conducted to determine the type or colour of the fabric
they are from. Forensic scientists can sometimes indicate the type of garment or
material from which they originated. Comparisons can also be made with suspects
clothing. Fibres and threads can be picked up with gloved fingers or tweezers and
wrapped in paper, then put in an envelope, which is then sealed and marked.
Fingerprints can be patent and may be left in a liquid such as blood. Photographs can
be taken as a lasting record. Fingerprints may be latent but may become more
identifiable with the use of powder or a chemical agent. An ultra-violent light may be
used if prints are ones where they would not usually be easily visible. Prints can be
Types of Evidence
Evidence can be divided into two categories:
Physical: also referred to as real evidence, consists of tangible articles such as hairs,
fibres, fingerprints and biological material.
Testimonial: statements or the spoken word from the defendant, a victim or
witness.
Physical evidence
The concept known as Locard's exchange principle states that every time someone enters
an environment, something is added to and removed from it. This principle is sometimes
expressed as 'every contact leaves a trace’ and applies to contact between individuals as
well as between an individual and physical environment. Scenes of crime officers always
work on the principle that physical evidence is left behind at every crime scene.
Testimonial evidence
Testimonial evidence is the spoken word of the witness, which could include either the
victim or defendant. Evidence must be admissible, which means complying with the rules of
evidence. For instance, in the Colin Stagg case, all the evidence relating to 'Lizzie' was
excluded by the trial judge.
Statements of witnesses will have been taken by each side and disclosed before the court
case. In court, testimonial evidence is usually given in the witness box with the opportunity
for the opposing side to cross-examine or question the witnesses' evidence.
Process of physical evidence collection
Bloodstains can be collected on sterile material, if still in a liquid form, and left to dry
at room temperature. Within 28 hours, they should be transferred to the laboratory
for the forensic scientists to examine. If the blood has already dried on material, the
article should be placed in a container, sealed and labelled.
Semen stains are often found on clothing or bedding and should be allowed to dry
on the material, then wrapped in paper and placed in paper bags. It is crucial in
offences of a sexual nature that evidence is secured and that a doctor examines the
victim. All appropriate clothing and other exhibits should be packaged separately.
Hair samples are likely to be on the clothing. If so, the clothing should be wrapped in
paper and submitted to the laboratory for examination. Any small fragments of hair
should be placed in the paper, which can be marked and sealed. Occasionally, the
analysis of hairs can reveal the possible race of the individual from whom they came
and the part of the body from which they originated.
Fibres and threads are often found on other items or caught in torn materials. An
examination can usually be conducted to determine the type or colour of the fabric
they are from. Forensic scientists can sometimes indicate the type of garment or
material from which they originated. Comparisons can also be made with suspects
clothing. Fibres and threads can be picked up with gloved fingers or tweezers and
wrapped in paper, then put in an envelope, which is then sealed and marked.
Fingerprints can be patent and may be left in a liquid such as blood. Photographs can
be taken as a lasting record. Fingerprints may be latent but may become more
identifiable with the use of powder or a chemical agent. An ultra-violent light may be
used if prints are ones where they would not usually be easily visible. Prints can be
