Chapter 5 and 7 Powerpoint
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Reconstruction Patterns
generally cannot be collected; documented only
Identification patterns
can generally be collected and preserved; documented and collected; involves comparison between Q vs K samples
Questioned Specimen
Q, unknown crime scene sample; unknown origin
Known specimen
k, control comparison sample; known origin
K vs. Q = not a match
Exclusion; K is excluded an the origin of Q
K vs. Q = not enough information to determine
inconclusive; no conclusion can be drawn either way
K vs. Q = match
inclusion, K is included as the origin of Q
Inclusions
known sample is included as your source; can be a person or an item associated with a person (finger, shoe, tire, weapon)
exclusions
a known and questioned specimen do not match and could have had a common origin; absolute; just as important as inclusions and identification; DO NOT CONFUSE WITH inconclusive
inconclusive
if there are a few details present that do match, but not enough for an id, the examiner cannot exclude that Q and K are from the same source
individualization pattern comparisons
• physical match • comparison of impression marks (footwear/tire mark; fingerprints; firearms and tool marks) • shape and form comparison (handwriting comparison / questioned document examination) Make sure same specimens are being compared. General orientation of impressions is being compared (left v right shoe) Compare class characteristics (category) Compare individual characteristics (what is different)
Class Characteristics
defines class or category that objects belong to; not sufficient to define individuality alone; two categories - general and limited; result of manufacturing (rips in jeans, pattern on the bottom of shoe. etc.)
General class characteristics
characteristics intentionally produced by the manufacturing process; standard for every make and model of the item
limited class characteristic
characteristics unintentionally produced by the manufacturing process; unique to a certain mold, imperfections in the mold used
individual characteristics
accidental/ unintentional; random marks from wear; sufficient number of these will allow an examiner to make an indentification
physical match
matches between or among pieces of randomly fractured, torn, or cut object that might show that the pieces were originally part of the same item (find the origin) Direct match: primary/first order Indirect match: secondary/second order
direct physical match can occur if:
• the fractured or torn pieces are from a solid object • the solid object is expected to fracture randomly • the pieces can be matched back together (capable of being realigned, cannot be forced back together, all of the pieces are available for a direct match. If there are pieces missing, it is an indirect match)
Examples of motors vehicle physical matches
paint chips; headlights; grill; exterior mirrors; lights; trim pieces
Examples of burglary physical matches
paint chips; wood; tools; glass; doors/trims
Examples of bicycle physical matches
reflectors; lights; tires; spokes
Examples of miscellaneous physical matches
buttons; fingerprints; knives; bones; stones
Indirect physical match can occur if
some portions of the item are missing; the item is not solid (fabric); the item has distorted or poorly define edges
An indirect match is often the result of
a complex pattern that reaches across the boundaries of each piece.
Examples of indirect matches
matches; paper documents; money; checks; stamps; sheet plastic; etc.