dactyloscopy
study of fingerprints
herschel
required Indians to put their fingerprints on contracts
used fingerprints as a means of identifying prisoners
henry faulds
claimed that fingerprints did not change over time
they could be classified for identification
alphonse bertillon
proposed body measurements as a means of identification
termed anthropometry
francis galton
developed a primary classification scheme based on loops, arches, and whorls
fingerprint system still used today
edward richard henry
in collaboration with galton, instituted a numerical classification system
fingerprint system still used today
why did the system evolve
Will West and William West looked alike and would match exactly with Bertillon's method; one was jailed for the crimes of the other
do fingerprints change during an individual's lifetime
no
ridge ending
island or short ridge
eye or enclosure
delta
bifurcation or fork
double bifurcation
trifurcation
minutiae
characteristics of ridge patterns
types of fingerprint arches
plain and tented
plain arch
tented arch
types of loops
radial and ulnar
radial loops
opens towards the thumb, right
ulnar loops
opens towards the pinky, left
plain/central pocket whorl
has at least one ridge that makes a complete circuit
contain a circle or spiral within the print
plain: has a symmetry core in the center, deltas near the bottom of the print
double loop whorl
made of two loops
contains an s shape
whorls
have two deltas and a loop
henry FBI classification system
each fingerprint is given a point value
visible (patent) prints
made after coming in contact with colored material such as blood, paint, grease, or ink
plastic prints
ridge impressions left on a soft material such as putty, wax, soap, or dust
impression fingerprints
latent fingerprints
not visible to the naked eye
consist of the natural secretions of human skin and require development for them to become visible
eccrine
secrets largely water, with both inorganic (ammonia, chlorides, metal ions, phosphates) and organic (amino acids, lactic acids, urea, sugars) compounds. Most important for fingerprints
sweat glands located on hands and feet
apocrine
secretes pheromones and other organic materials
sweat glands located in hair follicles
sebaceous
secretes fatty or greasy substances
ninhydrin
uses paper
object dipped or sprayed in ninhydrin, wait for 24 hours
purple-blue print
reacts with amino acids to produce a purple color.
soak suspected surface with ninhydrin solution and allow to dry
print should develop within 24 hours
cyanoacrylate vapor (super glue)
uses household items: plastic, metal, glass, and skin
heat sample in a vapor tent
white print
fumes react with water and other fingerprint constituents to form a hard whitish deposit
silver nitrate
uses wood and/or styrofoam
object dipped or sprayed
black or reddish brown under UV light
reacts with chloride to form silver chloride, a material that turns gray when exposes to light
reacts with salt found in sweat
iodine fuming
uses paper, cardboard, unpainted surfaces
in a vapor tent, head solid iodine crystals
brownish print (fades quickly)
must be photographed or sprayed with a starch solution
developing latent prints
requires substances that interact with secretions, causing the print to stand out against its background
it may be necessary to attempt more than one technique, done in particular order so as to not destroy the print
- cover surface with dust
- remove exc
other prints
lip - several common patterns
voice - electronic pulses measured on a spectograph
foot - size of foot and toes; friction ridges on the foot
shoes - can be compared and identified by the type of shoe, brand, size, year of purchase, and wear pattern
palm -
AFIS
- automated fingerprint ID system - a computer system for storing and retrieving fingerprints
- established in the 1970s
- search large files for a set of prints taken from an individual
- compare a single print, usually a latent print developed from a cr
IAFIS
- a persons fingerprints may be in one AFIS database but not another
- integrated automated fingerprint identification system which is a national database of all 10 print cards from all over the country
bertillon method
first biometry system
used in conjunction with AFIS
biometrics
used with AFIS
includes retinal or iris patterns, voice recognition, hand geometry
other functions:
control entry or access to places/computers
identify a person for security purposes
help prevent identity theft or control social services
ridge
appears dark on fingerprint image
valley
appears light on fingerprint image
dermis
innermost layer of skin
basal
middle layer of skin
epidermis
outermost layer of skin
loop
most common fingerprint pattern
have ridges that enter from either right or left and exit the same side they enter
arch
least common fingerprint pattern
have ridges that enter from one side of the fingerprint and leave from the other side with a rise in the center
whorl
looks like a bulls eye with two deltas
present in 30% of population
Fingerprints begin forming how many weeks into a female's pregnancy?
10
Ninhydrin and Superglue can be used to lift invisible prints because they react with what part of the print?
amino acids found in the sweat
When a fingerprint expert takes the witness stand and says he's absolutely certain two fingerprints match, he means he's found
at least 12 or more matching minutiae
accidental whorl
pores
small white dots inside the ridges
When collecting fingerprint evidence, what are two main precautions forensic detectives need to avoid doing?
adding fingerprints to evidence
destroying fingerprints already present
why cant fingerprints be destroyed
fingerprints grow back
scars on fingerprints make prints even more unique
what type of evidence are fingerprints considered
individual - can be linked back to a specific person; no two people have identical fingerprints
Explain how fingerprints are formed during fetal development.
the basal layer cells grow faster than the layers above and below it so it collapses and folds to form intricate shapes that make up the fingerprint
microns
one millionth of a meter or one thousandth of a millimeter
core
center of loop