Forensics

What type of print isn’t visible to the naked eye

latent

If you put your fingerprint ink on a card, what prints are you leaving?

patent

this type of print will be left behind in silly putty or bees wax

plastic

finger prints can be considered what evidence?

circumstantial, individual, and class

what are the parts of the fingerprint that leave black ink behind

ridges

what part of the fingerprints leave no print behind

valleys

what are some reasons why we have finger prints

sense of touch, better grip, easier perspiration

if a fingerprint has 2 deltas it’s definitely a…

whorl

if you dusted a crime scene and found a fingerprint, what kind did u find?

latent

when do prints start to form

10w in the womb

outermost layer of the skin

epidermis

layer in the skin where new skill cells are made

basal layer

ninhydrin and superglue react with what part of a latent print

amino acids found in sweat

what chemical can be used on wood or styrofoam and turns a print black or red-brown?

silver nitrate

fbi fingerprint data base

IAFIS

frenchman who created a system of body measurements to identify criminals

alphonse bertillon

silvernitrate can be used to lift latent prints because it reacts with what part of the print

salt found in sweat

which chemical produces a brown print when it sublimes that fades and should be photographed?

iodine

on the right hand, a loop opening towards the thumb would be..

radial loop

evolutionary purpose of fingerprints

grip things

Who created a system in 1896 that divided fingerprint records into a group based on arch, loop, whorl

sir edward richard henry

purpose of dermal ridges

provide friction so that you can pick up objects

substances present in finger prints

sweat, oil, salt, amino acids, carbohydrates

how would you locate latent prints on a dark surface

dust surface with fluorescent powder and shine a uv or blue light on surface

how to chemically develop a latent print on a piece of paper

ninhydrin- soak paper in solution, purple print shows up

iodine- expose paper to iodine fumes, get brownish print; fades quickly

what substance in fingerprints does cyanoacrylate react with to make a white print

amino acids

fbi database for fingerprint I.D.

IAFIS or NGI

what decisions can a fingerprint examiner make after comparing a crime. scene to a suspect print

inconclusive, conclusive (I.D.), exclusive

what other kinds of info can CSIs get from fingerprints besides pattern

DNA, particles from gunshot residue/explosives, chemicals in sweat

what parts on your body have dermal ridges

fingers, palms, toes, soles

ulnar vs radial

Ulnar loop → the fingerprint loop opens toward your pinky

Radial loop → the fingerprint loop opens toward your thumb

techniques to make latent prints visible

• Fingerprint powder – dust powder sticks to the print so you can see it

• Cyanoacrylate (superglue) fuming – fumes stick to the print and turn it white

• Ninhydrin – sprayed on paper; turns prints purple

• Iodine fuming – fumes make prints turn brown (temporary)

• Alternate light (UV/blue light) – helps prints glow so they stand out

how to do black powder technique

dust the fingerprint using a bursh that has the powder on it. once it’s visible and clear use a clear piece of tape and stick it onto it. press down then remove it. stick tape onto your backing card

Super glue fuming

• Good for: Plastic, metal, glass (non-porous)

• Reacts with: Sweat and oils

• Result: Print turns white

Ninhydrin

• Good for: Paper, cardboard (porous)

• Reacts with: Amino acids (from sweat)

• Result: Print turns purple

Iodine fuming

• Good for: Paper, cardboard

• Reacts with: Oils and fats

• Result: Print turns brown (temporary)

Silver nitrate

• Good for: Paper (especially old or wet)

• Reacts with: Salt (chlorides) in sweat

• Result: Print turns dark when exposed to light

using the old way of searching through 10 cards, how long could it take?

3 months

IAFIS

• Stands for Integrated Automated Fingerprint Identification System

• Old FBI fingerprint database

• Used fingerprints to identify people

NGI

• Stands for Next Generation Identification

• Replaced IAFIS

• Uses fingerprints plus palm prints, hand edge prints, and biometrics like iris scans and facial rec.

other data we can get from fingerprints

DNA, analysis of sweat to see what the other person touched or consumed, and minute particle analysis to see if they have certain particles on their fingers like explosives