Criminal Investigation in Practice - Analysis of the Procedures and Evidence Value

Procedure	Advantages	Disadvantages	Value
Speak to F.A.O	Speaking to the FAO can gain lots of in depth information about the crime scene and if anybody has entered the scene such as paramedics etc and if there are any areas that may have been a suspected break-in.	The FAO could possibly give misleading information about the crime scene such as the wrong focal point of the scene of the crime.	Speaking to the F.A.O can provide valuable evidence as their statement can lead to areas of the scene where the SOCO may not know to look as it may be away from the focal point of the scene.
P.P.E	PPE protects the crime scene from us and us from the crime scene. PPE also prevents contamination of evidence.	There aren't really any disadvantages of PPE apart from the possibility of cross contamination between different crime scenes.	This can provide valuable evidence as, by wearing PPE, evidence is less likely to be contaminated and therefore increases the value of evidence recovered from a scene.
Cordoning	Cordoning the crime scene can prevent contamination of evidence by the public or media. Cordoning can also give an idea to the SOCO as to where the crime scene starts.	However, cordoning in the wrong area could lead to the crime scene and evidence being contaminated or not collected.	Cordoning provides valuable evidence as it prevents contamination of the scene and can also give a wider picture from the focal point of the crime for the SOCO to investigate.
I.S.A	The Initial Scene Assessment can provide details about the scene that can be relied on later in court and later into the case as the photos and sketches can shown the location of items and evidence at the scene.	If details are missing from the Initial Scene Assessment, such as the weather conditions, the evidence has the potential to be thrown out of court because the evidence could have been destroyed by weather.	The initial scene assessment provides valuable evidence as it can "preserve" the scene which can lead to evidence being spotted later on in the case that wasn't collected at the scene.
C.A.P	The Common Approach Path prevents contamination of the scene as the people that enter the scene can use the CAP to get to evidence located around the scene.	The C.A.P needs to be followed in a crime scene however, if it is not followed, evidence could be destroyed and contaminated by people walking through the scene.	The C.A.P makes evidence valuable as if people stick to the C.A.P, then evidence won't be destroyed or contaminated and it will then lead to a conviction by not destroying or contaminating the evidence.
Chain of Custody	The chain of custody is necessary to prevent evidence being lost or tampered with as it logs who has looked at the evidence and analysed it.	The chain of custody can be a disadvantage as if it is not followed correctly, evidence could potentially be tampered with and contaminated.	The chain of custody provides valuable evidence as it keeps track of evidence and who has handled it and for what purpose it has been opened for. This can prove if any tampering has taken place.
Crime Scene Entry Log	A crime scene entry log can log who has entered a crime scene and for what purpose. It can also log if a SOCO has entered more than one crime scene in a day and explain if there are any cross contamination.	A crime scene entry log is useless if nobody uses it and just walks into the crime scene without logging in. This could cause contamination of evidence and the crime scene.	A crime scene entry log is extremely valuable as this can prove if someone has been at two or more crime scenes in a day and explain any evidence contamination.
Witness Statements	Witness statements can be extremely reliable sources of information as they can provide information about the crime committed.	Witness statements can also be misleading as shown in Loftus and Palmer's psychological study; depending on the questions that are asked, the witness can be misled on their account of what happened.	Taking witness statements at a crime scene can be valuable as the event is still fresh in the mind of the witness as the event will have recently occurred.