“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