FingerprintsChapter 14

History of Fingerprinting

ScientistDate(approximate)

Contribution to Forensics

Alphonse Bertillon

Henry Fauld

Francis Galton

Dr. Juan Vucetich

Sir Richard Edward Henry

History of FingerprintingAlphonse Bertillon• 1883 – First systematic

attempt at personal identification

• Used portrait parlé - verbal description of perpetrator’s physical characteristics and dress provided by an eyewitness

• And used anthropometry – a system of precise body measurements

• System used for over two decades

History of FingerprintingHenry Fauld• 1880 – Scottish physician

published articles suggesting that skin ridge patterns could be important in identification of criminals– Explained how fingerprints

were used to solve a crime– Offered to help set up system

at Scotland Yard; offered rejected

History of Fingerprinting

Francis Galton• 1892 – Published the textbook

Fingerprints– Discussed anatomy of fingerprint

and methods of recording– Introduced the three patterns –

loop, whorl, and arch– Demonstrated that no two prints

were identical and that prints do not change over a lifetime

• British government adopted fingerprinting as a supplement to the Bertillon system

History of Fingerprinting

Dr. Juan Vucetich

• 1891 – Argentinian police officer

• Devised a classification system for prints so that they can be filed and searched easily

• Although revised, it is still used in many Spanish speaking countries

History of FingerprintingSir Edward Richard Henry

• 1897– Proposed another type of classification

system adopted by Scotland Yards– Most English speaking countries use a

modified version

History of FingerprintingWill West• 1903• Proved Bertillon’s system inaccurate• Convict arrived at prison to find another William

West with the same body measurements and similar physical characteristics

• Fingerprints were use to distinguish prisoners

History of FingerprintsNew York City Civil Service Commission

• 1901

• First systematic and official use of fingerprints for personal identification

• Used to certify all civil service applications

Fundamental Principles of FingerprintsA Fingerprint is an Individual Characteristic; No

Two Fingerprints Have Yet Been Found to Possess Identical Ridge Characteristics.

• Galton calculated the possible existence of 64 billion different fingerprints!• Ridge Characteristics, also known as minutiae, are ridge endings, enclosures, and other ridge details that must match in two fingerprints in order for their common origin to be established• In judicial proceedings, a point-by-point comparison must be demonstrated• There are as many as 150 ridge characteristics on the average fingerprint

Fundamental Principles of Fingerprints

A Fingerprint Will Remain Unchanged During an Individual’s Lifetime

• The pattern of ridges determined by the dermal papillae, the boundary between the first two layers of skin

• Pores are present on the top layer releasing sweat and oil – this can be transferred to a surface when touched leaving an invisible impression – latent fingerprints

Fundamental Principles of Fingerprints

Fingerprints Have General Ridge Patterns that Permit Them to be Systematically Classified.

• All fingerprints are divided into three classes on the basis of their general pattern: loops, whorls, and arches

Refer to Fingerprinting 101 to identify the various classes of fingerprints.

Ridge Characteristics

• The individuality of a fingerprint is not determined by its general shape but by careful study of its ridge characteristics or its minutiae

• No two fingers have yet been found to possess identical ridge characteristics

Basic and composite ridge characteristics  (minutiae)

Minutiae Example Minutiae Example

ridge ending           bridge          

bifurcation           double bifurcation          

dot           trifurcation          

island (short ridge)           opposed bifurcations          

lake (enclosure)           ridge crossing          

hook (spur)          

opposed bifurcation/ridge ending

         

Ridge Characteristics Ridge Characteristics

• Ridge Dots• Bifurcations • Trifurcations• Ending Ridge • Ridge Crossing • Enclosures (Lakes) • Short Ridges (Islands)• Spurs (Hooks)• Bridges

Ridge DotsRidge Dots

• An isolated ridge unit whose length approximates its width in size             

                

BifurcationsBifurcations

The point at which one friction ridge divides into two friction ridges

           

 

Double Bifurcation     Opposed Bifurcation

TrifurcationsTrifurcations

• The point at which one friction ridge divides into three friction ridges 

Ending RidgeEnding Ridge

• A single friction ridge that terminates within the friction ridge structure

         

Ridge CrossingRidge Crossing

•    A point where two ridge units intersect       

Enclosures (Lakes)Enclosures (Lakes)

• A single friction ridge that bifurcates and rejoins after a short course and continues as a single friction ridge

Short Ridges (Islands)Short Ridges (Islands)

• Friction ridges of varying lengths

         

Spurs (Hooks)Spurs (Hooks)

• A bifurcation with one short ridge branching off a longer ridge

BridgesBridges

• A connecting friction ridge between parallel running ridges, generally right angles

Classification of Fingerprints

• System used by FBI converts ridge patterns on all 10 fingers into numbers in the form of a fraction

• Fingerprint cards can be classified into 1024 groups

• The presence or absence of a whorl pattern is the basis for the determination of the primary classification

Classification1. Fingers are paired in the following sequence:

R. Index R. Ring L. Thumb L. Middle L. Little

R. Thumb R. Middle R. Little L. Index L. Ring

2. If a whorl pattern is found on any finger in the first pair, it is assigned a value of 16; on the second pair, a value of 8; on the third pair, a value of 4; on the fourth pair, a value of 2; and on the fifth pair, a value of 1. Any finger have an arch or loop is assigned a value of 0.

3. Add all the values for the 10 fingers and then add 1 to both the numerator and denominator.

4. The fraction obtained is the classification.

For example:

16 + 0 + 0 + 0 + 0 + 1 17

=

0 + 8 + 0 + 0 + 0 + 1 9

Automated Fingerprint Identification Automated Fingerprint Identification SystemSystem

The AFIS (Automated Fingerprint Identification System) uses automatic scanning devices that convert the image of a fingerprint into digital minutiae that contain data showing ridges at their points of termination and the branching of ridges into two ridges (bifurcations).

AFIS has brought about a fundamental change to the way criminal investigators operate, allowing them to spend less time developing suspect lists and more time investigating the suspects generated by the computer.

Types of PrintsTypes of Prints Visible Prints are made when

the fingers touch a surface after the ridges have been in contact with a colored material such as blood, paint, grease or ink.

Plastic prints are ridge impressions left on a soft material such as putty, wax, soap or dust.

Latent Prints are impressions caused by the transfer of body perspiration or oils present on finger ridges to the surface of an object.

Locating Latent PrintsLocating Latent Prints

Locating latent prints requires the use of techniques that will make the prints visible.

Latent prints on hard and nonabsorbent surfaces (e.g., glass, mirror, tile and painted surfaces require the use of powders and/or Super Glue to make the prints visible.

Prints on soft or porous material (e.g., paper, cardboard, cloth) generally require treatment with one or more chemicals to make them visible.

Methods of Detecting Fingerprints • Each group will be assigned one of the

methods used for detecting fingerprints. • Read about the method in your book on

pages 417-424 and answer the following questions in your notes:– What type of print does it detect? – On which type of surface does it work best?– What is the process used to visualize the

prints and retrieve them?

• Type up your notes in a few concise lines on word document to present to the class.

Sometimes the most difficult aspect of fingerprint examination can be the location of the print.

Recent advances in fingerprint technology have led to the development of an ultraviolet image converter for the purpose of detecting latent prints.

This device, called the Reflected Ultraviolet Imaging System (RUVIS), can locate prints on most nonabsorbent surfaces without the aid of chemical or powder treatments.

RUVIS detects the print in its natural state by aiming UV light at the surface suspected of containing prints. When the UV light strikes the fingerprint, the light is reflected back to the to the viewer, differentiating the print from its background surface.

The transmitted UV light is then converted into visible light by an image intensifier. Once located in this manner, the crime-scene investigator can develop the print in the most appropriate manner.

RUVIS

Other techniques for lifting printsOther techniques for lifting prints

Iodine Fuming is a technique for visualizing latent fingerprints by exposing them to iodine vapors.

Sublimation is a physical change from the solid directly to the gas state.

Ninhydrin is a chemical reagent used to develop latent fingerprints on porous material by reacting with amino acids in perspiration.

Other techniques for lifting printsOther techniques for lifting prints

• Physical developer: a silver-based reagent formulated to develop latent fingerprints on porous surfaces.

• Super Glue Fuming: A technique used for visualizing latent fingerprints on non-porous surfaces by exposing them to cyanoacrylate vapors; named for the commercial product “Super Glue”.

Digital ImagingDigital Imaging

Digital Imaging is the process by which a picture is converted into a digital file.

When fingerprints are lifted from a crime scene, they are often not in perfect condition. This makes their analysis very difficult.

With the help of digital imaging software, fingerprints can now be enhanced for the most accurate and comprehensive analysis.