AC1.3 Explain how evidence is processed
Types of evidence
There are two main types of evidence: physical and testimonial. Physical evidence, also
referred to as “real evidence” is any tangible material such as hairs, fibers, fingerprints and
murderweapons. Physical evidence is the most important piece of evidence to secure a
conviction in court, it can be analysed in the lab to allow forensics to draw conclusions.
Testimonial evidence is written or verbal evidence usually given by eyewitnesses and expert
witnesses, it is the most common type of evidence but is also more easily disputed in court.
Testimonial evidence
Testimonial evidence can be used by both the defence and prosecution, all testimonial
evidence must follow the “rules of evidence.” The rules of evidence can be defined as: the
legal rules that outline what types of evidence are allowed in court and whether it counts as
“admissible” evidence, if it is not admissible it will be disallowed and the jury have to
disregard it when making their decision. Evidence is classed as admissible if it has been
maintained in the proper manner, relates to the facts of the case or can prove or disprove
points provided at trial. Testimonial evidence is used more heavily by the prosecution
however the defence will get a chance to cross-examine any witness produced.
Cross-examination grants the defence the opportunity to ask the witness questions about the
event in question as well as their testimony. The validity of a witness and how much reliance
is placed on the testimony they give is up to the magistrate and the jury. If a witness refuses
to attend court to give testimony, they may be subpoenaed- the only exception to this rule is
the accused, their spouse and anyone deemed mentally unable to give testimony.
Case Study- Menendez brothers
The Menendez brothers were arrested and charged with the murder of their parents in 1990.
Lyle and Eric accused their father of sexually abusing them for years before the murders.
Many of the eyewitnesses were from the Menendez family, with their cousin testifying that
Erik had disclosed the abuse to him when they were children. During the second trial, the
Judge disallowed the defence to use the sexual abuse, hindering the case as it removed the
basis to conclude that they had killed their parents out of fear of further abuse.
Physical Evidence
Physical evidence is the most vulnerable evidence to obtain, especially so if the crime scene
is in an outdoor environment. An outdoor crime scene can lead to a loss or contamination of
evidence, the weather can wash away vital biological evidence, animals will be attracted to
the scent of a body and can start to pick away and eat it, getting rid of evidence. If the
weather is hot, it can dry out evidence left at the scene, similarly, if it is raining or snow is
melting, it can wash away evidence. If a body is well hidden or blends in with its
environment, people will be unaware that it is infact a crime scene and walk on/past it,
contaminating the scene. The Locard exchange principle states that every time a person
enters an environment, they leave traces and fibres of the environment they were in before
as well as taking traces from this environment when they leave. This can affect physical
evidence as, if proper cross-contamination procedures are not followed, it can add fibres and
take them away from a scene, as the exchange principle states, ‘every contact leaves a
trace.’ The risk of cross-contamination is greatest if the scene isn’t secured properly and as
soon as possible.
Types of evidence
There are two main types of evidence: physical and testimonial. Physical evidence, also
referred to as “real evidence” is any tangible material such as hairs, fibers, fingerprints and
murderweapons. Physical evidence is the most important piece of evidence to secure a
conviction in court, it can be analysed in the lab to allow forensics to draw conclusions.
Testimonial evidence is written or verbal evidence usually given by eyewitnesses and expert
witnesses, it is the most common type of evidence but is also more easily disputed in court.
Testimonial evidence
Testimonial evidence can be used by both the defence and prosecution, all testimonial
evidence must follow the “rules of evidence.” The rules of evidence can be defined as: the
legal rules that outline what types of evidence are allowed in court and whether it counts as
“admissible” evidence, if it is not admissible it will be disallowed and the jury have to
disregard it when making their decision. Evidence is classed as admissible if it has been
maintained in the proper manner, relates to the facts of the case or can prove or disprove
points provided at trial. Testimonial evidence is used more heavily by the prosecution
however the defence will get a chance to cross-examine any witness produced.
Cross-examination grants the defence the opportunity to ask the witness questions about the
event in question as well as their testimony. The validity of a witness and how much reliance
is placed on the testimony they give is up to the magistrate and the jury. If a witness refuses
to attend court to give testimony, they may be subpoenaed- the only exception to this rule is
the accused, their spouse and anyone deemed mentally unable to give testimony.
Case Study- Menendez brothers
The Menendez brothers were arrested and charged with the murder of their parents in 1990.
Lyle and Eric accused their father of sexually abusing them for years before the murders.
Many of the eyewitnesses were from the Menendez family, with their cousin testifying that
Erik had disclosed the abuse to him when they were children. During the second trial, the
Judge disallowed the defence to use the sexual abuse, hindering the case as it removed the
basis to conclude that they had killed their parents out of fear of further abuse.
Physical Evidence
Physical evidence is the most vulnerable evidence to obtain, especially so if the crime scene
is in an outdoor environment. An outdoor crime scene can lead to a loss or contamination of
evidence, the weather can wash away vital biological evidence, animals will be attracted to
the scent of a body and can start to pick away and eat it, getting rid of evidence. If the
weather is hot, it can dry out evidence left at the scene, similarly, if it is raining or snow is
melting, it can wash away evidence. If a body is well hidden or blends in with its
environment, people will be unaware that it is infact a crime scene and walk on/past it,
contaminating the scene. The Locard exchange principle states that every time a person
enters an environment, they leave traces and fibres of the environment they were in before
as well as taking traces from this environment when they leave. This can affect physical
evidence as, if proper cross-contamination procedures are not followed, it can add fibres and
take them away from a scene, as the exchange principle states, ‘every contact leaves a
trace.’ The risk of cross-contamination is greatest if the scene isn’t secured properly and as
soon as possible.
