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Fingerprints Fingerprints

Fingerprints - PowerPoint Presentation

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Uploaded On 2016-10-20

Fingerprints - PPT Presentation

What you Need to Know but may already know History Sir Edward Henry of London Metropolitan Police developed modern system of identifying criminals by their fingerprints in 1900 The Henry system as it is sometimes known was so useful in criminal investigations that it was adopted aroun ID: 478445

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Presentation Transcript

Slide1

Fingerprints

What you Need to Know

(but may already know)Slide2

History

Sir Edward Henry (of London Metropolitan Police) developed modern system of identifying criminals by their fingerprints in

1900

The Henry system (as it is sometimes known) was so useful in criminal investigations that it was adopted around the worldSlide3

The Henry System

He classified fingerprints into 8 types based on 4 shapesSlide4

Fingerprint Info

No two people have the same fingerprints

Your fingerprints should stay the same throughout your life. They change only because of accident, illness or surgery.

Prints are based on “hills” and “valleys” on your skin.Slide5

At the Scene

Fingerprints are either visible or latent

Visible prints show up by themselves

Dirt, soot, blood, ink etc.

Easy to spot

Easily photographed

Latent prints are hidden

Produced by perspiration

Have to be made visible with powder and lifted off surface using special tape (then photographed)

On fabric or paper latent prints are made visible with chemical dye (then photographed)Slide6

In the Lab

If fingerprints are found at the crime scene, the next step is to find out who they belong to

Victims can be fingerprinted to eliminate them

Convicted criminals have fingerprints taken and stored

Computers can rapidly tell if prints found at a crime scene match those of a known criminal

AFIS (automated fingerprint identification system)

Who else may be fingerprinted?Slide7

Hmm. Interesting.

British detectives believed that 2 prints matched when 16 specific features of one print matched the features in the other

American detectives believed it was enough to match 8 or 12 features

Recently the number of matching features has become less relevant and balanced by whether there are any major differences between the 2 prints