Chapter 6 Forensics

Cyanoacrylate

"super glue" fumes react with water and other fingerprint constituents to form a hard, whitish deposit

Ninhydrin

A chemical reagent used to develop latent fingerprints on porous materials by reacting with amino acids in perspiration

accidental whorl

A mix of different patterns. Cannot be classified as any other pattern.

trifurcation

branch into three

fingerprints are formed deep within the dermis layer of the skin

false

the type of powder used to dust prints will vary depending upon the weather conditions when the print is lifted

false

palm prints

lines can be identified and may be used against suspects; included in the fingerprints scans, 20-30% of the prints found

double loop whorl

made up of any two loops combined into one print

What are fingerprints/formation of fingerprints

on the basal layer of the skin, formed within the first trimester or 10 weeks of gestation, the epidermis protects it

radial minutiae pattern

opens towards pinky

ulnar minutiae pattern

opens towards thumb

Fingerprints that are actual indentations left in some soft material such as clay or putty are referred to as

plastic fingerprints

Minutiae

small or trivial details, trifling matters

How are latent fingerprints collected?

Dust it with fingerprint powder, sometimes you can use magnetic fingerprint powder, You use tape to collect fingerprints

How are fingerprints analyzed?

They scan the fingerprint, AIFIS identifies the type and marks the minutiae, inputs for info database, person running it identifies any possible matches

How reliable is fingerprinting as a means of identification?

Since humans identify the fingerprints, there is always a possibility that something could be messed up; reliable, but not 100% effective; it has gotten better over time with more technological advances

is it possible to alter fingerprints?

Yes and no, fingerprints may be altered but they usually go back to normal. John Dillinger tried to alter his but he essentially made his prints more unique.You can put acid or chemicals on fingertips, you can surgically remove them, or you can switch the fingerprints upside down in surgery.

Can fingerprints be altered or disguised?

Yes, but usually it is not permanent or not done very well.

ten card

a form used to record and preserve a person's fingerprint

latent fingerprints

a hidden fingerprint made visible through the use of powders or other techniques

the presence of two deltas in a fingerprint indicate

a print is a whorl pattern

plastic fingerprints

a three-dimensional fingerprint made in soft material such as clay, soap, or putty

delta fingerprint

a triangular ridge pattern with ridges that go in different directions above and below a triangle

patent fingerprints

a visible fingerprint that happens when fingers with blood, ink, or some other substance on them touch a surface and transfer the pattern of their fingerprint to that surface

fingerprints are a result of oil and secretions from skin mixing with dirt

true

is is important to always photograph a fingerprint before you attempt to lift it

true

similar print or ridge patterns can also be found no the toes

true

IAFIS

Integrated Automated Fingerprint Identification System

another way to make prints more visible is to apply certain chemicals. what component of a fingerprint chemically reacts with silver nitrate?

Chloride from salt in perspiration on the print combined with silver nitrate to form silver chloride.

compare and contrast fingerprint searches today using IAFIS with fingerprint searches that might have occurred 25 years ago

Fingerprint searches are much easier now than 25 years ago because we have a computerized system that runs a fingerprint and finds a match with it in almost no time due to a computerized formula. 25 years ago they had to check by hand for a match and there were probably more mistakes.

outline the steps in taking a ridge count from a fingerprint

First locate the delta and the core of the fingerprint. Count the ridges in between these two locations

what does the future of fingerprinting look like?

Machines have gotten better, Nanoparticles in powder to make prints possible, how to detect what you have touched

summarize how fingerprints are formed

They are formed during pregnancy (10th week of gestation) in the mother's womb when the fetus is only a couple inches long. When the basal layer creates new skin cells they fold and bend to create patterns

Central pocket loop whorl

Two deltas, a line drawn between the delta does not go through the central pocket

another way to make prints more visible is to apply certain chemicals. what component of a fingerprint chemically reacts with cyanoacrylate?

amino acids

another way to make prints more visible is to apply certain chemicals. what component of a fingerprint chemically reacts with ninhydrin?

amino acids

fingerprints are formed when?

at 10 weeks' gestation ( pregnancy )

loop fingerprint

begins at one side of the finger, loops around the ridge ends at the same side of the finger that it began.

plain whorl pattern

bullseye with two deltas

another way to make prints more visible is to apply certain chemicals. what component of a fingerprint chemically reacts with iodine fuming?

carbohydrates in latent prints

Plastic prints must be dusted or treated in order to identify the ridge patterns

false

fingerprints of the left hand are mirror images of the fingerprints on the right hand

false

fingerprints are generally considered to be a form of class evidence

false, they are a form of individual evidence

It is necessary to obtain a full print from a suspect in order to compare his fingerprint with a fingerprint found at the crime scene

false, you do not need the full print

fingerprint ridge count

from center of the core to center of the delta

whorl fingerprint

has a central circle area with ridges circling around it. Ridges DO NOT go from one side to the other

Iodine fuming fingerprint

heat up iodine crystals, combines with the carbohydrate in your prints and makes a brown print, fades quickly

silver nitrate fingerprint

salt in your sweat combines with silver nitrate to create the print

the use of fingerprints in identification is not perfect because

the current technology depends on humans to analyze the information, and humans make mistakes

IAFIS improves the speed and accuracy of fingerprint searches because it electronically accesses fingerprints from local, state, and national agencies

true