AC 1.1 - Evaluate the effectiveness of the roles of personnel involved in
criminal investigations
Crime Scene Investigators
Role
A crime scene investigators role is to collect and preserve evidence from the crime scene.
Their main responsibility is to ensure that the evidence at the scene is not contaminated as
this would therefore mean it would be inadmissible in court. They work together with the
police to decide what evidence is vital and decide the best way in order to gather it. They
photograph the crime scene, as well as any surrounding areas that contain evidence, using
the common approach path. Once they have obtained all the evidence, they have to pack
and document everything so it is ready to be sent off for analysis by forensic specialists. In
addition to this, they may also attend post mortems and give evidence in court.
Effectiveness
Expertise - CSI’s are experts in their field as they undergo thorough training and many also
have a degree in a science related field. This would imply that they have a great deal of
expertise as they have had the necessary training in order to carry out their role effectively.
Availability - CSI’s are available 24/7 as they work on an on-call basis. This means that they
could be called to a crime scene at any time of the day. This is essential as of course crimes
can be committed at any time, and so it is important that crime scene investigators can arrive
at the scene quickly in order to obtain evidence before it may be possibly contaminated by
factors such as the weather.
Cost - Each CSI gets paid a salary, and so this will therefore incur additional costs to the
investigation.
Other evaluative points
- The samples that CSI’s collect may be a hazard to their health and safety, so these
risks need to be calculated and the appropriate measures taken in order to minimise
the risk of harm
- The role can take a toll on CSI’s mental wellbeing due to the nature of the scenes
that they may attend to.
- The weather could contaminate the crime scene
- They may be able to prove a suspect's innocence through DNA or fingerprint testing.
Case Example - Amanda Knox
- Exchange student found dead in her flat in Italy, friend Knox suspected of murder.
- Contamination of evidence, failures to document evidence, planted evidence to
falsely incriminate
Forensic Specialists & Scientists
Role
Once evidence has been collected from the crime scene by CSI’s, it is passed over to the
Forensic Specialists and Scientists. Their role is to interpret and analyse the evidence in
relation to the crime scene. They analyse a range of evidence, such as blood and other
bodily fluids, in order to try and find DNA. This is the aim of most evidence analysis, as
, finding DNA means the person responsible for the crime is often identified and found.
Effectiveness
Expertise - Forensic scientists possess a great deal of specialist knowledge that is vital in
investigations. They are able to interpret evidence which could lead to proving if a suspect is
innocent or guilty, so they have a big role to play within an investigation. This expertise is
especially valuable in complicated and advanced criminal cases, as the criminal may also
possess knowledge which prevents evidence being linked to them.
Availability - Forensic scientists typically work during the normal working week, which is
Monday to Friday. This could be an issue as some cases may require evidence to be
analysed urgently in order to catch the suspect as soon as possible, and so waiting for a
forensic scientist to be available would cause delays in the investigation. However, some
forensic scientists work on an on-call basis, which means that they can work on high priority
cases as they unfold which would greatly help the investigative process.
Cost - As forensic scientists are highly qualified individuals, this also means that their
salaries and work they provide is expensive. This would mean that the use of forensic
scientists in investigations would increase the cost of the investigation overall, and perhaps
means that not all evidence would be analysed as it might not be financially feasible.
Other evaluative points
- The work that forensic scientists do is subjective, and thus that means that different
forensic scientists may interpret evidence differently. This could cause issues in the
courtroom, as the defence and prosecution’s experts may give conflicting evidence
which would confuse the jury and make it more difficult for them to come to a verdict.
- An expert, such as a forensic scientist, could mislead the court, whether it be on
purpose or as a result of a mistake in their work. This ultimately leads to miscarriages
of justice where either the suspect is wrongly found guilty or not guilty. An example of
this is the case of Sally Clarke who was found guilty for murders she did not commit
as a result of an expert's mistake.
- Issue of contamination - If evidence is contaminated in the analysis process this can
cause issues such as evidence being mixed up or incorrectly interpreted. This of
course would lead to problems with the investigation, perhaps in accusing the wrong
suspect or letting someone go due to the evidence surrounding them being lost.
Case Example - Sally Clarke
- Wrongly convicted of the murder of her two sons as a result of the expert witness,
Professor Sir Roy Meadows, giving evidence that was based on wrong information
(See AC3.2 for more detail)
Case Example - Adam Scott
- Falsely accused of rape after his DNA was contaminated, leading him to spend 5
months in custody charged with rape. This shows how contamination of evidence can
affect a criminal investigation.
Case Example - Sarah Payne
- Sarah Payne was a young girl was abducted and murdered by a previously convicted
pedophile Roy Whiting
- Used fibers from sweatshirt found in van to link to the presence of Sarah there, found
