Evidence and Investigation review

Evidence and Investigation

Review

Can I recognize evidence of recent human
activity and recognize evidence of animal
activity in a natural outdoor setting?

● What is evidence?
● What are examples of human activity?

○ Footprints
○ Tire prints
○ Garbage or debris left behind

Footprints

● Footprints closer together indicates walking
● Footprints further apart indicates running
● Deeper prints =heavier person
● Shallower prints =lighter person
● Shoe size
● If more than one person was present
● If the person was leaving or arriving

Multiple Choice

Examining the footprints found at a crime scene would most likely help an investigator determine

• the age of a suspect

• whether a suspect is male or female

• whether there is more than one suspect

• the time the suspect committed the crime

Multiple Choice

Which of the following statements outlines a proper procedure to use when completing a chromatography test?

• The chromatography paper should be left in the water until all the ink has disappered.

• The chromatography paper should be dipped completely under water and then quickly removed

• The bottom 1 cm of the chromotagraphy paper should touch the water, but the ink line should not.

• The chromatography paper should be dipped 1 cm into the water only deep enough so that the ink line is just under the waetr level.

Tire Tracks

● Type of tire found on a vehicle
● Approximate size and mass of vehicle based on

depth of the tracks

● Direction vehicle was travelling
● Imperfections in the tire
● Wear of the tire tread

Soil Samples

● Colour
● Types of rocks in it
● Decaying plant and animal material it contains
● Chemical makeup
● All can help determine where the soil might have

come from

Multiple Choice

Texture, pattern, and strength are all terms that are most often used when describing

• tire tracks

• soil samples

• fibres and fabrics

• handwriting samples

What is animal activity?

● Animal tracks in snow are useful -estimate how

big and how it moved

● Farther apart stride = running
● Dogs and cats have four toes but only dog show

claws

● Show picture

Handwriting samples

● Look at form of handwriting- shapes of letters, slant, angles,

connections and curves

● Line quality,thickness of line =instrument used
● Arrangement on the page
● Content-spelling, punctuation
● Also what kind of paper and ink can determine how old paper is
● Chromatography is a method of analyzing complex mixtures

(such as ink) by separating them into chemical from which they
are made

Multiple Choice

Which of the following pairs of characteristics is the most helpful when analyzing a handwriting sample?

• slant of letters and letter formation

• slant of letters and ink colour

• pen type and letter formation

• pen type and ink colour

Multiple Choice

When analyzing a handwritten report, paper chromatography can be used most effectively to determine the

• author of the report

• time of day the report was written

• type of ink used to write the report

• type of pencil used to edit the report

Multiple Choice

Some characteristics of a Writing Sample: colour of ink, type of pen, type of paper, slant of letters, way letters are joined

Which two characteristics listed above would be most helpful when conducting a handwriting analysis?

• type of pen and type of paper

• slant of letters and type of pen

• colour of ink and the way letters are joined

• slant of letters and way letters are joined

Fingerprints

● No two individuals have the same
● Latent prints are invisible prints caused by transfer of

perspiration (sweat) from skin onto another surface

● Visible prints made by contact of the skin with a colored

material prior to leaving the print on a surface

● Plastic prints are impressions of prints left in a malleable

surface

Fingerprint types

1. Loops -line that enter and exit on the same side of the print

Th the most common type

Fingerprint types

2. Arches- lines that start on one side of the print, rise into hills
and then exit on the other side of the print

Fingerprint types

3. Whorl- circles that do not exit on either side of the print

Fingerprint types

4. Composite or Mixed

● Special procedure used to make fingerprints more visible-

using light or dark colored powders to highlight fingerprints is
called dusting

Multiple Choice

A police officer lifted a suspect's fingerprints from a car that had been broken into.

Number of Fingerprints Lifted From the Car

Part of the Car Partial Fingerprints Full Fingerprints

door handle 8 2

mirror 5 5

trunk lid 6 4

window 4 6

According to the information above, which part of the car would be the best source of the suspect's fingerprints?

• door handle

• mirror

• trunk lid

• window

Hair samples

● Can place a suspect at scene of a crime but considered

inconclusive evidence as it varies a great deal even when
taken from same person

Clothing samples

● Test fibers or match to a suspect
● Look at strands, color, texture, weave pattern, how it responds

to when it is wet, burned and how it can be stretched

● Two main types of fabric used in any piece of clothing

○ Natural fibers (made from plant/animals-wool, cotton,

silk, leather, linen and fur)

○ Synthetic fiber (man-made-polyester, nylon,rayon,plastic

Evidence vs. Inference

● Observation vs. evidence

Inference must be based on the evidence you find or see not assumptions you make
● Eyewitness accounts not always reliable
● More vocabulary review
● Motive-a reason for doing something,
● Autopsy-examining a body to determine cause of death
● alibi-a claim or piece of evidence that one was elsewhere when an act, typically a criminal one, is alleged to have taken

place.