development of fingerprinting what did sir francis galton discover in the 1800s? ridge...

Development of fingerprinting

What did Sir Francis Galton discover in the 1800s?

Ridge characteristics, or “Galton points.”What are they?

Different formations of lines on a fingerprintExamples?Line endings, dots, islands, bifurcations

Copyright © 2010 Christine Beck Lissitzyn

Class vs. Individual characteristics

What elements of fingerprints are class characteristics?

Loop, whorl, and arch. Why?Because 60% of people have loops,

35% have whorls and only 5% have an arch.

If all you can identify is one ridge ending, is it a class or individual characteristic?


Declaring a “match”

What is the ACE-V process? Analysis—broad review to check quality, one

print; often used to exclude Comparison – compare ridge characteristics to

eliminate or include; quantitative likeness Evaluation – done visually; qualitative likeness Verification – process repeated by another

technician.


Red Flags

What are red flags in the Analysis process? See Plaza I.

Fat ridges – may be two overlappingDifferent amounts of pressureSimilar ridge characteristics close to

each other – may be “double tap.”“shadow ridges” in furrows – may mean

two prints deposited


Madrid bombing latent print


Comparison stage, p. 144

How did this differ in 1973 compared with the AFIS system?

What does the computer do? Circle ridge characteristics and mark direction with

tail. Locate the “center” and “delta.” Add number of circled characteristics Give “ridge count,” number of ridges between each

identified Create a “map” of the characteristics


What does the examiner do?

Eliminate some ridge characteristicsReposition some tailsTell the computer if he is sure what

finger it isVisually check the computer results

against the prints it identifiesDeclare an opinion


What opinions can the examiner give?

IdentificationEliminationInconclusive


What are the subjective elements?

What does subjective mean?Examiner uses training and experience

to make judgments about:How many prints are in latent printRed flags – not one printWhether AFIS has correctly identified a

ridge char.Whether a top candidate can be eliminated

due to place or circumstance.


Is the first candidate always the match?

Chris Grice says 75% of the time.Is the candidate with a score of 1,000

necessarily a match?


Fingerprints and Daubert

Why did State v. Abreu decide fingerprinting id. met Daubert?

Because the judge held it was generally accepted.

What did the court say on p 148?“the court has wide latitude in deciding

how to determine reliability. . . .[it] did not clearly err in giving greater weight to the general acceptance factor.


Madrid prints


Would Grant be convicted without the Fingerprint? DNA?

If Grant won his appeal, the state would not be able to use the DNA.

If the court had required the jury to find the fingerprint could only have been left at the time of the crime beyond a reasonable doubt?

What was the corroborating evidence to the fingerprint?


The full set of PowerPoint slides is available upon

adoption.

Email [email protected] for more information.

development of fingerprinting what did sir francis galton discover in the 1800s? ridge...

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characteristics copyright

bifurcations copyright

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class characteristics

circle ridge characteristics

individual characteristics