7 S's of Crime Scene
What is the first and second things that should be done at a crime scene?
Secure the scene, separating the witnesses
Define Locard’s principle of exchange
This states that when a person comes into contact with an object or another person a cross-transfer of physical evidence can occur.
What makes a hair sample individual evidence?
The hair sample must have the follicle which contains DNA
What are the three categories of fingerprints, and which one is the most common?
Loop, arch, whorl. Loops are most common
Name three examples each of class and individual evidence (be specific)
Class: Fibers, physical evidence like a gun, pollen
Individual: Hair follicle, fingerprints, glass all from one source
When scanning and seeing the crime scene name 4 major things you should be looking for?
Points of entry and exit, identify the primary/secondary crime scene, possible pieces of evidence
Name three examples of trace evidence that could cross transfer.
Skin cells, fibers or debris from clothing, hairs, Pollen, glass fragments, makeup, soil
Provide three examples of natural fibers and three of synthetic fibers
Natural: wool, silk, linen. Synthetic fibers: Nylon, Polyester, acrylic
Describe the process of fingerprint formation
The basal layer of the skin grows faster and produces bumps that form the ridges of your prints
What are the three types of ballistics and give a brief description of each
Internal Ballistics – what happens inside the weapon
External Ballistics – what happens after the bullet leaves the barrel
Terminal Ballistics – what happens when the bullet hits the target
What makes a good observer (2 major things)?
Pay attention details of people and details of the crime scene
Name two ways CSI prevents leaving behind trace evidence
PPE including gloves, masks, and hazmat suits, AND limiting who enters and leaves the scene, AND securing the scene
What is the difference between natural fibers and synthetic fibers
Natural have cortex, cuticle and medulla and all look different. Synthetic fibers have none of those features and all look the same
How many deltas are found on a whorl and how many are found on a loop?
Two for a whorl and one for a loop
What is the difference between a radial crack and concentric crack?
Radial cracks appear from the unloaded side and grow towards the loaded side and away from the point of impact. Concentric cracks form from the loaded side to the unloaded side and between the radial cracks connecting them.
What needs to be included in a sketch label (6 things)?
Case number, date, time, location, name of sketch artist and name and victim
For the following pieces of trace evidence, provide an example of a location and type of crime
Broken glass, pollen, metal filings
Broken glass/car crash or burglary, pollen/garden or park, metal filings/garage or workshop
What is the importance of determining the direction of the cuticle?
Provides the direction of growth, aging the hair, can be useful for drug/chemical analysis
Looking at the following picture, name the type of print and the different minutiae points A-D.
Bridge
Bifurcation
dot/island
Ridge end
What are two ways to find the density of glass?
Find the volume and mass of the glass fragment
Suspend the item in different solutions of different known densities and see which layer it settles in.
What are the 7 S’s of CSI?
Securing the Scene
Separating the Witness
Scanning the Scene
Seeing the Scene
Sketching the Scene
Searching for Evidence
Securing and Collecting Evidence
What affects the extent of cross transfer?
Intensity, duration, type of material.
A hair sample is collected and has a follicle, what does that indicate about how the hair got there?
It was pulled out rather than falling out naturally
Looking at the following picture, name the type of print and the different minutiae points A-D.
Eye
Delta
Island/dot
Delta
What are three ways to find the volume of an object?
LxWxH
Displacement
Using archimedes principle