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Forensic Science Final -Study Guide 2013
Chapter 1: Introduction
1. What is Forensic science?
Application of science to law
2. People to know:
a. Bertillion First system of anthropometry
b. Galton Galton pointed out that there were specific types of fingerprint patterns. He described and
classified them into eight broad categories. 1: plain arch, 2: tented arch, 3: simple loop, 4: central
pocket loop, 5: double loop, 6: lateral pocket loop, 7: plain whorl, and 8: accidental
c. What is Locard’s exchange principle. Evidence will be taken & left behind.
3. In Court:
a. What is the Frye Standard? There must be a general acceptance of scientific evidence.
b. What are the qualifications of an expert witness?
c. Describe the CSI effect. The media portraying an inaccuracate view of forensic science:
speed of results, forensic scientists solve the cases. Every crime scene has evidence.
4. List and describe the types of evidence analyzed in the specialized crime lab units.
physical science unit
forensic engineering
toxicology unit
latent fingerprint unit
forensic odontology
biology unit
document examination unit
firearms unit
evidence collection unit
photography unit
Forensic computer
What types of evidence are researched using the following Forensic databases:
a. NIBIN -ballistics
d. AFIS- fingerprints
b. SICAR- shoeprints/impressions
e. PDQ- paint
c. CODIS- DNA
f. IBIS-ballistics
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Chapter 2: The Crime Scene
5. What are the first responsibilities of the first officer on the scene?
safety of individuals; secure scene
6. What are the methods used to record a crime scene?
photography, note taking, sketch
7. What should be included on a crime scene sketch? Dimensions, location of points of entry,
compass, date, location & type of evidence recorded, while processing scene.
Chapter 3: Physical Evidence
8. List the types of physical evidence that could be found at a crime scene.
blood, saliva, fingerprints, tire marks, tool mark impressions, bullet casings, weapon, blood spatter
9. Describe the methods for packaging the following evidence:
a. Wet/blood soaked items - paper bag (NOT airtight)
b. Items from an arson investigation (explosives or charred debris)- air-tight glass container
c. Hair and fibers - paper bindle or air tight container
10. Describe the chain of custody.
each investigator must initial and date and package. Responsibility of crime scene processors,
forensic technicians, scientists, examiners.
11. Define the following in terms of characterizing evidence and determining whether it came from a
single source:
a. Identification determine what the evidence is.
b. Comparison determine if the evidence is the same as another piece of evidence or control
samples.
12. What is the difference between class and individualized evidence? Provide 3 examples of each.:
Class: evidence that can be linked to a subset of individuals; blood type, new shoe print, blue car
Individual: can be linked to a specific person – fingerprint, DNA, 2 pieces of torn shirt with fracture
patterns that match
Forensic Pathology, Entomology & Anthropology
13. What are the 5 manners of death?
natural, homicide, suicide, accidental, undetermined
14. Define cause of death & provide 2 examples.
cause: the incident that led to death (stabbing, shooting, drowning, suffocation, heart attack)
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15. Define mechanism of death & provide 2 examples.
The biological impact on the body that resulted in death: exsanguinations; hypoxia
16. What are algor mortis, rigor mortis, & livor mortis?
algor: cooling of body; rigor: stiffness of body after death; livor: pooling of blood after death that
shows specific color pattern once fixed.
17. Name the insects that arrive first and last on a decomposing corpse.
first: blow fly; last: beetles
18. Name the parts of the corpse that decompose the quickest and the slowest.
flesh: quickest; bones: slowest
19. How can bones be used to determine gender and age?
Gender: pelvis, cranium, long bones (femur)
Age: fusion of bones
Chapters 8 and 10: Serology and Bloodstain Pattern Analysis
20. List 3 presumptive blood tests.
kastle-meyer; lumninol; hemastix.
21. What antigens are present on each blood cell type?
AB
22. Describe the reaction of agglutination. When would this type of reaction occur?
clumping of antibodies with cells containing antigens recognized by those antibodies.
anti-A with A blood cells will clump
23. Sketch a blood droplet that was dropped passively from an angle of 90O.Circular drop
24. Sketch a blood droplet that was deposited from an angle of 10O and note its direction of
movement with an arrow.
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Arrow pointing down for those shown below.
25. Sketch a blood droplet that was dropped from a low height vs. a higher height.
higher height: larger diameter
26. Sketch 3 blood droplets with a common area of convergence in 2-D.
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27. What method can be used to determine the area of origin in 3-dimensional space? String method
28. How would the size and range of droplets differ between those deposited at low or medium or
high velocities? Gunshot (high velocity) smaller diameter droplets spread over large area; misty
Low velocity (knife, hammer): larger drops spread over smaller area
29. How would the pattern of droplets left by an individual who was walking vs. running be different?
walking: drops closer together; running: drops father apart.
30. Define each of the following:
a. Linear cast off pattern:
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b. Arterial spray pattern bright red oxygenated blood
c. Void pattern
d. Contact pattern
e. Flow pattern
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Chapter 9: DNA
31. What is DNA? Dexoyribnucleic acid. Contains unique genetic information.
32. What are the basic building blocks of DNA? nucleotides
33. What are the bonding pairs for DNA bases? A-T & G-C
34. Define PCR and how it can be used. To amplify (copy) large amounts of DNA from very small
amounts
35. Describe how DNA is analyzed using RFLP and gel electrophoresis.
Restriction enzymes are used to cut DNA into fragments which are then run on a gel. Smaller
fragments migrate faster than larger fragments.
36. Describe how an RFLP gel can be used to identify a match between a victim’s blood and the
suspect.
37. Which easy-to-get cells are commonly used for routine DNA analysis? Cheek (buccal) cells
Chapter 11: Hair & Fibers
38. Sketch and label the 3 major structures of a human hair.
39. How does the medullary index differ
between human and animal hair?
40. What is a follicular tag? Why is it useful
forensics?
in
Follicular
attached
tag is tissue from a hair follicle that is still
to the root end contains DNA
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41. Define synthetic and natural fibers and provide the most common examples of each.
synthetic: man-made, nylon polyester
natural: plant-derived; cotton, silk
Chapter 15: Fingerprints
42. When are friction ridges formed on the fingers? What is their purpose?
43. Is it possible to permanently alter fingerprints without disfigurement of fingers? What layers of
skin would need to be changed?
No. Dermal papillae. (1-2mm beneath surface of outermost layer).
44. Are there circumstances when two people would have identical fingerprints? No. Of 50 million
recorded fingerprints in FBI database, none is identical to another.
45. List (in order of most to least common) and sketch the three major fingerprint patterns.
Loops 65%; Whorls 30%; Arches 5%
46. What is the primary classification system?
Who first
developed this system?
Henry
system: A 16 is assigned for either print of
the first
pair containing a whorl, an 8 is assigned for either print of the second pair containing a whorl, a 4
is assigned for either print of the third pair containing a whorl, a 2 is assigned for either print of
the fourth pair containing a whorl, a 1 is assigned for either print of the last pair containing a
whorl. A zero is assigned for all arches and loops. A final 1 is added to the numerator and
denominator.
Right Index
Right Ring
Left Thumb
Left Middle
Left Little
Right Thumb Right Middle
Right Little
Left Index
Left Ring
47. Sketch & label examples of the following
characteristics:
a. hook/spur
ridge
b. bifurcation
c. ridge ending
d. islands.
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48. How are two fingerprints determined to be a match?
Same relative locations of ridge characteristics imparts individuality to print.
49. Describe the following printsand give an example of each
a. visible: can be seen, print contacts a colored material such as blood, paint orink.
b. Plastic: impression of print on soap, putty, wax, dust
c. Latent: not readily visible, left by oil, amino acids, sweat.
50. What is a porous surface? Provide an example.
Absorbant surface; paper cardboard, cloth
51. Describe the following chemical methods used to develop latent prints:
Method
Best Surface
Bonds to
Resulting appearance
Dusting
Drawbacks
Nonabsorbent
nonporous
Oil, sweat
Black, gray
messy
Porous, paper
Fatty oil
brown
poisonous
Paper, porous
Protein, amino acids
Purple, blue
Paper only, stains
fingers.
nonporous
Amino acid, protein,
salt
white
permanent
Iodine
Ninhydrin
Superglue
Chapter 16: Impression Evidence- Firearms, Tool Marks, Tire tracks, Teeth Marks
52. What is the function of the grooves in a rifle?
accuracy & speed
53. How is the gauge of a shotgun determined?
diameter of shotgun barrel is inversely related to gauge
54. What type of individualized evidence can be gained from shells and cartridges?
striation markings from magazine, firing pin on shells & cartridges
55. Describe how the distance from where a gun was fired can be estimated based on gunpowder
residue. Specific patterns are left depending on the distance from where gun was fired.
56. Which lab tests can be done to reveal gun powder patterns?
greiss & Ir photography
57. When should an individual be tested for gunshot residue (GSR) to ensure the most effective
results? Sooner the better
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58. Describe the proper procedures to the collection and packaging of the following evidence:
Firearm evidence must be marked for identification (usually a tag on the trigger guard) and a chain
of custody must be established.
a. Gun found submerged in lake collect in water and bring to lab.
b. discharged bullets at a crime scene use gloves, tweezers
c. a crow bar used to gain entry to a home package
d. a window frame with a crow bar impression take picture, impression with dental stone if
possible
e. a tire track in the garden in front of the window take picture & impressions
59. Chapter 17: Questioned Documents
60. Define and provide 2 examples of questioned documents Letters, passports, contracts, receipts
61. Describe the types of evidence that might be obtained from:
a. printer or copy machine toner, ink,
b. a note handwritten in ink handwriting, ink chromatography
c. a used notepad use light to see if impression (indentation) was made
62. Describe how an investigator would obtain a sample of handwriting from a suspect.
Dictate same passage many times to see if consistent.
63. Describe how handwriting may change with age and how this might or might not help to use the
sample as evidence. Doesn’t usually change after adulthood is reached.
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