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Bullet Comparison and Identification (Identification (Consecutive…
Bullet Comparison and Identification
Identification
Consecutive Matching Striae - A process in which the number of matching striae are used to determined whether or not two objects correspond to one another
AFTE Theory of Identification - 1) the comparisons made must be in "sufficient agreement" 2) The markings must be able to be duplicated and result in the same and/or similar patterns 3) Although matching patterns is subjective, it is based on science
Pattern Identification - The process in which an examiner determined whether or not two objects correspond to one another
Sufficient Agreement and Best Known Match - Making a match is based off of an examiner's experience in their ability to determine whether or not two objects came from a common origin
Physical Characteristics - Include class (general characteristics), Individual (unique characteristics), and subclass characteristics
AFTE Range of Conclusions
Inconclusive - Can include situations in which there is some agreement on the class characteristic but not identification can be made, or agreement on class but disagreement on the individual characteristics
Elimination - Based on sufficient disagreement on both class and individual characteristics, meaning there are no patterns that match
Identification - Typically based on the amount of patterns that match
Unsuitable - Include fired bullets that can not be used for comparison due to the damage
Bullet Examination - Involves the comparison of fired bullets to determine whether or not they were fired from the same firearm by examining the patterns produced on it
Microscopic Procedures
Recovered Firearm With Related Evidence - In this case, the fired bullets that are recovered can be compared along side a test fired bullet to determine if the patterns that are produced can be considered a match
Evidence Without Related Firearm - In this case, fired bullets can be compared along side laboratory standards
Recovered Firearm Without Related Evidence - In this case, firearms are test fired to determine what kind of patterns are produced on the fired bullet
Case Linkage - A large number of bullets that are collects from unsolved cases are kept and used as comparisons for future cases
Casting - There may be situations in which an examiner may not have access to the physical bullet that needs to be examiner. In this case, a cast in made of the bullet which can be sent out to the examiner to make their comparisons
Dillon, H. John. “Module 11 :: Bullet Comparison and Identification” Firearm Examiner Training, projects.nfstc.org/firearms/.