Chapter 6 Fingerprints

Fingerprints

are a reproduction of friction skin ridges found on the palm side of the fingers and thumbs

no two fingers have yet been found to possess identical ridge characteristics

Why is a fingerprint an individual characteristic?

unchanged during an individual’s lifetime

What will a fingerprint remain?

general ridge patterns

What do fingerprints have that permit them to be systematically classified?

minutiae

The individuality of a fingerprint is not determined by its general shape or pattern, but by the careful study of its ridge characteristics, known as ________.

identity, number, and relative location

What of the minutiae imparts individuality to a fingerprint?

bifurcations, ridge endings, ridge dots, and enclosures

What are some common fingerprint ridge characteristics?

150

There are as many as ________ minutiae on the average finger.

True

Currently in the U.S., there is no predetermined minimum number of friction ridge characters which must be present in two impressions in order to establish positive identification.

point-by-point comparison

In a judicial proceeding, an expert must demonstrate a ________ in order to prove the identity of an individual.

Epidermis

The outer layer of the skin

Dermal papillae

The layer of cells between the epidermis and dermis. It is responsible for determining the form and pattern of the ridges on the surface of the skin.

to enlarge during growth

Once the dermal papillae develop in the human fetus, the ridge patterns will remain unchanged throughout life except…

perspiration

Each skin ridge is populated with pores leading to sweat

glands, from which ________ is deposited on the skin

perspiration is transferred onto that surface, leaving the finger’s ridge pattern (a fingerprint).

Once the finger touches a surface…

latent fingerprints

Some prints are invisible to the eye and are commonly referred to as

loops, arches, and whorls

All fingerprints are divided into three classes on the basis of their general pattern:

60-65%

How much of the population has loops?

30-35%

How much of the population has whorls?

5%

How much of the population has arches?

Loop

must have one or more ridges entering from one side of the print, recurving, and exiting from the same side

ulnar loop

If the loop opens toward the little finger, it is called a(n) _________.

radial loop

If the loop opens toward the thumb, it is called a(n) ________.

type lines

The pattern area of the loop is surrounded by two diverging ridges known as _______

Delta

the ridge point at or nearest the point where two type lines diverge. All loops must have one.

Core

the approximate center of the loop pattern

Plain, Central pocket loop, Double loop, Accidental

What are the whorl groups?

type lines and a minimum of two deltas

What do all whorl patterns have?

circuit

A plain whorl and a central pocket loop have at least one ridge that makes a complete ________.

The pattern is a plain whorl

What happens if an imaginary line drawn between the two deltas within these patterns touches any of the circular ridges?

the pattern is a central pocket loop

What happens if no such ridge is touched between the two deltas within these patterns?

Double loop whorl

made up of two loops combined into one fingerprint.

An accidental

either contains two or more patterns, or is a pattern not covered by the other categories. May consist of a combination loop and plain whorl or loop and tented arch.

Arch

the least common of the three general patterns, are divided into two distinct groups: Plain, Tented

Plain arch

formed by ridges entering from one side of the print, rising and falling, and exiting on the opposite side (like a wave).

Tented arch

similar to the plain arch except that instead of rising smoothly at the center, there is a sharp upthrust or spike, or the ridges meet at an angle that is less than 90 degrees

type lines, deltas, or cores

What do arches not have?

Analysis, Comparison, Evaluation, and Verification

What is the four-step process to identify and individualize a fingerprint?

Analysis

identify points of comparison and external factors

Comparison

compare the questioned print at 3 levels

Evaluation

determine a conclusion

Verification

the examiner’s conclusion is confirmed by a second examiner

3

How many levels of comparison are there?

Level 1

encompasses the general ridge flow and pattern configuration

Level 2

includes locating and comparing ridge characteristics or minutiae

Level 3

includes the examination and location of ridge pores, breaks, creases, scars, and other permanent minutiae

1,024

Using primary classification, all fingerprint cards in the world could be divided into ________ groups.

Primary Classification

First, fingers are paired up, placing one finger in the numerator of a fraction and the other in the denominator.

The presence or absence of the whorl pattern

What is the basis for the determination of the primary classification?

The fraction thus obtained is the primary classification

If a whorl pattern is found on any finger of the first pair, it is assigned a value of 16; on the second pair, an 8; on the third pair, a 4; on the second pair, a 2; and on the last pair, a 1. Any finger having a loop or arch is assigned a 0. After values for all 10 fingers are obtained, they are totaled, and a 1 is added to both the numerator and denominator.

1/1

Approximately 25% of the population falls into the ________ category; that is, all their fingers have either loops or arches.

True

A fingerprint classification system cannot in itself unequivocally identify an individual; it will merely provide the fingerprint examiner with a number of candidates, all of whom have an indistinguishable set of prints in the system’s file

AFIS

Automated Fingerprint Identification System

to scan and digitally encode fingerprints so that they can be subject to high-speed computer processing

What is the main ability of AFIS technology?

converting the image of a fingerprint into digital minutiae that contain data showing ridges at their points of termination (ridge endings) and their branching into two ridges (bifurcations)

How does AFIS aid in classifying and retrieving fingerprints?

the computer produces a list of file prints that must be examined by a trained fingerprint expert.

What happens when the search is complete?

allows for the creation of local systems at the county and city levels

Why do AFIS systems come in all sizes?

NGI (Next Generation Identification)

In 2014, the FBI integrated its IAFIS into the…

Visible Prints

when fingers touch a surface after the ridges have been in contact with a 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

the application of a powder

How are latent prints deposited on hard and nonabsorbent surfaces developed?

treatment with a chemical

How are prints on porous surfaces developed?

Powders

are available in a variety of colors, can be applied with a brush or magnetic wand, and adhere to perspiration and/or body oils of the print

black (black carbon) and gray (aluminum dust)

What are the most common powders?

Super Glue

is approximately 98-99% cyanoacrylate ester, a chemical that actually interacts with and visualizes a latent fingerprint

Super Glue Fuming

develops latent prints on nonporous surfaces, such as metals, electrical tape, leather, and plastic bags

when fumes from the glue adhere to the print

How does development occur with Super Glue fuming?

using either a fuming chamber (for up to six hours) or a handheld wand that heats a small cartridge containing cyanoacrylate

How can Super Glue® fuming be accomplished?

fluorescence

Fingerprints are treated with chemicals that would induce ________ when exposed to lasers or high-intensity light sources (“alternate light sources”) such as quartz halogen, xenon arc, or indium arc light sources

RAM, RAY, and MRM 10

What dye combinations used in conjunction with Super Glue fuming have been effective in visualizing latent fingerprints by fluorescence?

iodine fuming, ninhydrin, and physical developer

Examiners use various chemical methods to visualize latent prints on porous surfaces, such as…

Iodine Fuming

involves heating iodine crystals that cause vapors which combine with latent prints to make them visible.

Iodine prints

are not permanent and will fade, making it necessary to photograph the prints immediately

Ninhydrin

reacts chemically with trace amounts of amino acids present in latent prints to produce a purple-blue color and is the chemical method of choice for porous surfaces

Physical developer

is a silver nitrate-based reagent used to develop prints when other chemical methods are ineffective and is useful for developing prints on porous objects that may have been wet at one time

it should be preserved in its entirety

If the object is small enough to be transported without destroying the print…

A photograph

must be taken before any attempts at preservation are made

lifting

Prints on large immovable objects that have been developed with a powder can best be preserved by “________” with a broad adhesive tape

Digital Imaging

the process by which a picture is converted into a digital computer file

enhanced for the most accurate and comprehensive analysis

With the help of digital imaging software, fingerprints, which are often not in perfect condition, can now be…

The “compare” function

places two images side by side and allows the examiner to chart the common features on both images simultaneously

Alphonse Bertillon

The first systematic attempt at personal identification was devised and introduced by ________ .

Bertillon system (anthropometry)

A system of identification relying on precise body measurements is known as ________ .

Sir Edward Henry

The fingerprint classification system used in most English-speaking countries was devised by ________.

True

The first systematic and official use of fingerprints for personal identification in the United States was adopted by the New York City Civil Service Commission.

Is not

The individuality of a fingerprint ________ determined by its pattern.

Minutiae characteristics

A point-by-point comparison of a fingerprint’s ________ must be demonstrated to prove identity.

Fingerprints

________ are a reproduction of friction skin ridges.

Dermal papillae

The form and pattern of skin ridges are determined by the ________.

Dermal papillae

A permanent scar forms in the skin only when an injury damages the ________.

Cannot

Fingerprints ________ be changed during a person’s lifetime.

Loops, whorls, and arches

The three general patterns into which fingerprints are divided are ________, ________, and ________.

Loop

The most common fingerprint pattern is the ________.

Arch

Approximately 5 percent of the population has the _________ fingerprint pattern.

Radial

A loop pattern that opens toward the thumb is known as a ________ loop.

Type lines

The pattern area of the loop is enclosed by two diverging ridges known as ________.

Delta

The ridge point nearest the type-line divergence is known as the ________.

One

All loops must have ________ delta(s).

Core

The approximate center of a loop pattern is called the ________.

Plain whorl

If an imaginary line drawn between the two deltas of a whorl pattern touches any of the spiral ridges, the pattern is classified as a ________.