FingerprintsDactyloscopy

History

The use of fingerprints can be traced back

to Ancient China when emperors and

artists used their fingerprint to sign their

work.

In the 1860s, William James Herschel

studied fingerprints as a hobby and had

people sign for their pensions with their

print to avoid fraud.

History Continued

The first time fingerprints were used to

exonerate a suspect was 1880 in Japan by Dr.

Henry Faulds.

In the 1890s, Sir Francis Galton conducted

extensive research on prints and wrote a book

which convinced the British government to adopt

fingerprints as a supplement to identify people.

Sir Francis Galton proposed the three major

pattern types of loops, arches, and whorls.

History Continued

In 1892, in Argentina, Detective Alvarez used bloody fingerprints found at a crime scene to identify a murder suspect – first time!

After 1904, fingerprints were widely used in criminal investigations in the US, and in 1924, the FBI centralized fingerprints records and created an identification division.

What are fingerprints?

Fingerprints are impressions of the ridges

of the fingertips.

No two people have the exact same

fingerprints due to the identity, number,

and location of minutiae!

Fingerprints NEVER change during a

lifetime.

Fingerprints develop BEFORE BIRTH!

Fingerprint Minutiae

Minutiae are shape and ridge characteristics.

There are 9 types of minutiae:

Bifurcation or fork

Ending ridge

Dot or island

Enclosure or eye

Spur or Hook

Bridge

Trifurcation

Ridge crossing

Double Bifurcation

Video Lecture - Characteristics of Fingerprints

Fingerprint Minutiae continued

Fingerprint Minutiae continued

Fingerprint Minutiae Continued

There are about 150 different ridge

characteristics on a given print!

Identifying Fingerprint Types

The pattern area is surrounded by two

diverging ridges known as type lines.

The ridge point nearest the type line

divergence is known as the delta.

The core is the approximate center of the

pattern. Arches DO NOT have type lines

or deltas.

Skin

Skin is composed of layers of cells.

The outermost layer is the epidermis. The

inner skin is the dermis.

Between these two layers is a boundary

made up of dermal papillae. This layer

determines the pattern of ridges on the

skin.

Skin Layer Diagram

Skin Continued

Each skin ridge is covered by a single row

of pores that are openings of the ducts for

the sweat glands.

Sweat and oil therefore get deposited on

any surface touched by the hands = Latent

Prints

About 85% of people are secretors.

Can I Remove My Fingerprints?

Scarring to “erase” one’s fingerprints only

serves to make them more recognizable.

Removing Fingerprints Continued

John Dillinger (1930s) tried dipping his

fingers in acid.

Removing Fingerprints Continued

Roscoe Pitts (1950s) was most successful

at obliterating his fingerprints by having

skin from his chest surgically grafted to his

fingertips.

Classification of Prints

The three classes of fingerprint patterns

are not found in the same percentages in

the population

Loops = 65%

Radial Loop (toward thumb) or Ulnar Loop (opposite,

toward pinky)

Arches = 5%

Plain Arch or Tented Arch

Whorls = 30%

Plain Whorl or Central Pocket Whorl or Double Loop

Whorl or Accidental Whorl

Loop

How to Determine if a Fingerprint is a

Loop

Loops have ONE Delta and a Core

at the top of the innermost loop!

Arch

Arch Tented Arch

How to Determine if a Fingerprint is

an Arch

Arch Tented Arch

There are NO deltas or cores in an “arch”

fingerprint!

Whorl

How to Determine if a Fingerprint is a

Whorl

Whorls have TWO Deltas and a core

in the middle of the spiral

Classification Continued

Classification assigns a formula to a set of

prints so they can be readily located and

filed. It consists of numbers and letters

(we’ll go over this in a lab).

At the scene…

There are three types of prints an

investigator looks for.

Visible Prints – made when in contact with a

material such as blood or paint

Plastic Prints – made in putty, soap, wax or

dust

Latent Prints - invisible

Visible Prints

Plastic Prints

Latent Prints

Latent prints must be processed to

become visible.

Prints left on non-porous surfaces can be

dusted with fingerprint powder.

Prints left on porous surfaces must be

treated chemically.

Latent Prints

Latent Prints

Latent Prints

Prints as Evidence

Most prints found at crime scenes are

partial prints.

There is no definite number of minutiae

that must be matched but about 8-14 are

usually used to declare a match.

Fingerprint Types & subgroups

Video - Classification of Fingerprints

Fingerprint

Minutiae

Find the

Minutiae!