FINGERPRINTS“Fingerprints cannot lie,

but liars can make fingerprints”

-Unknown

A LITTLE HISTORY… First systematic

attempt at personal identification devised by Bertillon in 1883

Three parts:AnthropometryPortrait parléphotographs

BERTILLON CARD 11

measurements Detailed

descriptionsDiseaseAccidentsDeformitiesScars, tattoos,

moles, warts, etc.

AND ELSEWHERE… Evidence in early

China William Herschel

(India) used handprints for legal documents

WHY ARE THEY IMPORTANT? It’s basically an impression of the

pattern of ridges on the last joint of a person’s finger

They are so useful for ID because:The ridges are unique and characteristic They are consistent over a person’s lifetimeThere is a systematic classification

Are humans the only ones? Why do we have them?

POINT 1 – THEY ARE UNIQUE Individuality of a print is not determined

by general shape or pattern, but in a careful study of the minutiae (the ridge characteristics)

POINT 2 – THEY DON’T CHANGE Remember that skin is layers of cells Nearest the surface – epidermis Inner skin – dermis Boundary of cells separating the dermis

and epidermis – shape is made up of dermal papillae – that determines the form and pattern of the ridges

Each ridge populated by single row of pores that are openings for sweat glands – perspiration (along with oils) is transferred onto surfaces when touched

YOUR PRINT… CLOSE UP

POINT 3 – THERE’S A SYSTEM All fingerprints

divided into three classes based on general pattern: loops (60-65%)whorls (30-35%)arches (~5%)

IN DA LOOP ulnar loop –

ridges open towards pinky finger

radial loop – ridges open towards thumb

core – center of the pattern

KEEP IN MIND WHICH HAND…

Ulnar loop (on left, will flow out of right)

Radial loop (on left hand, will flow out of the left)

WHORLY-WHORL must have at

least two deltas and a core

four typesplaincentral pocketdoubleaccidental

LOOK CLOSER…

plain- two deltas with curving ridges central pocket – notice different deltas/different ridges

LOOK CLOSER…

double whorl accidental – follows whorl rules, but may include other pattern types

GOLDEN ARCHES? simplest to spot ridges enter one

side and exit the opposite

plain arch – no upthrust in middle of print, ridges flow smoothly from one side to another

tented arch – has upthrust greater than 45 degrees in middle of print