BTEC Level 2 Applied Science: Forensic Science -
You should be able to:
Explain the meaning of ESLA and state the type of evidence that can be recovered with it
For two types of evidence, state how they might be recovered from a scene of crime
Explain the meaning of latent when the word is applied to a fingerpint at a crime scene
State Locard's Law and say why you think TWO-
Part 6) Recovering Evidence at the Crime Scene:
By now, the CSI will have searched the scene and identified and marked-
The CSI will recover each different type of evidence using a method that prevents the items from becoming contaminated or damaged. Hairs and fibres, for example may be recovered either by using a pair of tweezers (if the fibres are easily visible), or by using soft-
A Reminder about Locard's Law
Put simply, Locard's Law tells us that "every contact leaves a trace." Let's think about this in a little more detail.
When evidence is deposited at the scene by the person who carried out the crime, a ONE-
Locard's "law" or "Exchange Principle" tells us that when a crime is committed, physical evidence will be left at the scene of crime, and the perpetrator will take traces of evidence away from the scene of crime.
We see below someone attempting to force entry to a shop till. If they have used a tool such as a screwdriver, it is likely that a toolmark will be made on the till. The CSI will be able to make a cast of the toolmark, and if the tool is recovered, the toolmark can be "matched" to the tool. Footwear marks will also be left at the scene, and these can be recovered by the CSI. If shoes from a suspect are recovered, these can be "matched" to the footwear mark.
If the store used "Smart Water", the person who carried out the crime will unknowingly have been "tagged" with a fluorescent dye when they committed the crime. This evidence can be used to uniquely place that person at the crime scene well after they have left the scene.