THE SCIENCE OF FINGERPRINT IDENTIFICATION - or - How to Make Your Point in the Courtroom!

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THE SCIENCE OF FINGERPRINT IDENTIFICATION- or
-How to Make Your Point in the Courtroom!

• Prepared by
• David Ski Witzke
• Vice President, Sales Marketing
• PC Pros MORE HITS

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The Science of Fingerprint Identification

• The first misconception about latent print
  identification is
• Latent print examiners dont just count points!

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So whats my point?

• Latent print identification relies on three
  levels of detail NOT just points!
• Level 1 detail -- Ridge flow (patterns)
• Level 2 detail -- Ridge formations (ridge
  endings, bifurcations, dots, or combinations
  thereof)
• Level 3 detail -- Ridge path deviation (ridge
  structure or formation, which includes ridge
  width, shape, pores and other details)
• Level 1, 2 and 3 Details...  a thumbnail
  explanation of terms coined by David Ashbaugh

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Level 1 DetailRidge Flow
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Level 1 DetailRidge Flow

• Ridge flows make up three distinct pattern types
• Loops
• Arches
• Whorls

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Level 1 DetailPattern Types
Left slant loop
Whorl
Plain arch
Double Loop Whorl
Right slant loop
Tented arch
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Level 2 DetailFriction Ridge Formations

• Friction skin ridges on the hands and feet create
  distinctive features that are grouped into three
  basic characteristics (also known as points)
• Bifurcations (or the splitting of a single ridge
  into two ridges)
• Ridge endings (or point at which a ridge ends)
• Dots

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Level 2 DetailFriction Ridge Formations
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Level 3 Detail Ridge Path Structure
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Latent Print Examiners are allowed to make
positive identifications

• 1.  With appropriate training
• 2.  With appropriate experience
• 3. With appropriate ability
• 4. When using the scientific procedure of ACE-V
• Analysis
• Comparison  
• Evaluation  
• Verification

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The Scientific Methodology called ACE-V

• Analysis the qualitative and quantitative
  assessment of Level 1, 2, and 3 details to
  determine their proportion, interrelationship and
  value to individualize. 
• Comparison to examine the attributes observed
  during analysis in order to determine agreement
  or discrepancies between two friction ridge
  impressions. 
• Evaluation    the cyclical procedure of
  comparison between two friction ridge impressions
  to effect a decision, i.e., made by the same
  friction skin, not made by the same friction
  skin, or insufficient detail to form a conclusive
  decision. 
• Verification an independent analysis,
  comparison and evaluation by a second qualified
  examiner of the friction ridge impressions.  

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In summary, the ridge flow (level 1 detail) the
type, relative location (position) and
orientation of all minutiae (level 2 detail) and
ridge structure (level 3 detail) match.
Therefore these two prints can be considered a
match!
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