Trace Evidence - General + Glass Flashcards
Edmund Locard created the worlds first ________
Crime laboratory in 1910
What is Locards Exchange Principle
When ‘A’ comes into contact with ‘B’ something from ‘A’ will be left on ‘B’ and vice versa
Every contact leaves a trace!!!!
What are the 8 types of Trace Evidence
Blood Glass Fibres Hair Plants Saliva Semen Soil
What is persistence?
Persistence describes the duration in which evidence remains in a location before it is further transferred, degraded, or collected as evidence
What are the 5 conditions that affect Persistence
Activity of or around the evidence location Environment surrounding evidence Location Time from transfer to collection Type of evidence
what is the definition of Contamination
Undesired transfer of information between items of evidence
What are the 3 ways Contamination can be limited?
Properly designed facilities
Protective clothing
Quality cantered protocols regarding handling and packaging of evidence
What are the 8 recovery techniques?
Shake Brushing Taping Vacuuming Swabbing Hand picking Extracting Liquids/Gases
What are the 8 methods of Glass
Colour Thickness Optical shape manufacturing process Sharp/blunt/clean/dirty edges Chemical properties Refractive index Physical fits
What are the two types of fractures in Glass?
Radial fracture
Concentric fracture
What are the 4 rules of collecting glass?
Collect 6 pieces of glass from the window frame NOT the floor
Double glazing - both sides of glass
Car window = handful of fragments
Secure ina box taped to the bottom or in a ridged container for smaller samples
In regards to glass, the ___ _____ a person is the ____ ______ they are to have glass on their _______
Further away
Less Likely
Clothing
4 additional places glass can be on an individual
Hair
Texture of clothing
Turn ups on trousers,
Pockets
What is the decreasing evidential value stages of glass
Hair combings/cuts in shoe uppers
Outer clothing (upper and lower)/pockets/turnups
Glass embedded in sole of shoes
