Fingerprints cannot lie but liars can make fingerprints

“Fingerprints cannot lie, but liars can make fingerprints” -Unknown

� First systematic attempt at personal identification devised by Bertillon in 1883 � Three parts: �Anthropometry �Portrait parlé �photographs

� 11 measurements � Detailed descriptions �Disease �Accidents �Deformities �Scars, tattoos, moles, warts, etc.

� Evidence in early China � William Herschel (India) used handprints for legal documents

� 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 lifetime �There is a systematic classification � Are humans the only ones? � Why do we have them?

� Individuality of a print is not determined by general shape or pattern, but in a careful study of the minutiae (the ridge characteristics)

� 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

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

� ulnar loop – ridges open towards pinky finger � radial loop – ridges open towards thumb � core – center of the pattern

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

� must have at least two deltas and a core � four types �plain �central pocket �double �accidental

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

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

� 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