Fingerprints History Earliest recognition of uniqueness of fingerprints & their suitability for...

Fingerprints History

• Earliest recognition of uniqueness of fingerprints & their suitability for personal identification apparently came from the ancient Chinese.

• They used a thumbprint in lieu of a signature on legal conveyances & even criminal confessions. This was due to the prevalence of illiteracy making fingerprinting a practical measure.

Fingerprints

• First scientific recognition of fingerprints: from certain late 17th century writings.

• 1684 Dr Nehemiah Grew report described ridges & pores on hands & feet. This started it all.

• Johannes E. Purkinje – first person to devise a system of classifying fingerprints.

Fingerprints

• He published thesis in 1823 describing 9 fingerprint patterns, gave each a name & set down rules for individual identification, many of which are still followed today.

• Two men recognized use for identifying people from fingerprints (Japan & India) working at same time but not aware of each other’s work.

Fingerprints

• 1877 – William Herschel sought to implement his fingerprint system in Bengal jails but couldn’t get permission.

• Dr. Henry Faulds, Scottish physician & surgeon discovered that oil & sweat from pores resulted in latent (invisible) prints that could be developed with powders. He used this technique to exonerate a man accused of burglary using fingerprints

Fingerprints

• Faulds & Herschel argued over who was first in pioneering fingerprinting. Faulds was referred by Charles Darwin to Sir Francis Galton to settle argument.

• Galton was interested in who pioneered it. He wanted to join in the new field.

Fingerprints

• Galton published textbook, Finger Prints, in 1892 giving credit to Herschel as “the first to devise a system for the use of fingerprints for identification” & most important, setting forth a practical method of classification - Not just by patterns but by entire set of fingerprints of an individual so they could be filed.

Fingerprints

• Edward Henry, Herschel’s successor in India, became interested in fingerprinting & he began work on his own classification system.

• He simplified where possible, and added complexity where needed. Overall, he shaped the whole into a fully practical & workable system.

Fingerprints

• Completed in 1899, his system was published in book form the following year.

• In 1901, the Henry system of fingerprint classification & filing was implemented in England & Wales.

• With later modifications by the FBI, the Henry system continues in use to the present day.

Fingerprints

• 1894 Britain: primary identification method: bertillonage (system of anthropometry created by Alphonse Bertillon involving recording 11 measurements.

• By turn of century, Scotland yard began to rely on fingerprints. Reluctantly, Bertillon added space on his record cards but for the right hand only.

Fingerprints

• 1903, in the U.S. came case that marked the beginning of the end of bertillonage.

• 5-1-1903: Will West sent to Leavenworth Penitentiary. Bertillon measurements taken. Clerk said he looked familiar, found another card with similar measurements & photo looking like him. Name on card was “William West”. So both men were brought together in same room.

Fingerprints

• Will & William West denied being related but were actually identical twins. They had similar fingerprint patterns, ear patterns & wrote to the same brother, 5 sisters & Uncle George.

• Fingerprints were taken & one man could be distinguished from another without fail.

• The next day, the Henry method was adopted by the prison.

Fingerprints

• In 1924, U.S. Congress established at the then-Bureau of Investigation (now FBI) the Identification Division to serve as nation’s repository of all fingerprints records.

• During gangster era (20’s-30’s) finger-printing captured imagination of American public when it was seen as the premier scientific weapon for dealing with public enemies.

Fingerprints

• Public Enemy #1, John Dillinger, sought to have fingerprints altered at same time he had plastic surgery to alter his face.

• Result was a portion of each print scarred, but more than enough was left to match to his file prints. Scar patterns call attention to themselves. Like everything in nature, no two scar patterns are exactly alike.

Fingerprints

• Today FBI’s Identification Division is largest unit with over 2,600 employees.

• More than 200 million sets of prints represent more than 68 million individuals on file in the Criminal Justice Information Services Division.

• Non-criminal fingerprint files are kept elsewhere.

Classification of Fingerprints

• Second reason to leave Bertillon method: theft of Mona Lisa from the Louvre on August 21, 1911.

• Thief left clear thumbprint on glass from painting. Bertillon had no method of classification for fingerprints on his cards.

• Two years later, thief arrested, print from left thumb, prints on file from right hand.


• Sir Edward Henry lived to see his system of fingerprint classification become adopted & succeed.

• With some modification, the Henry system is the one we use today!

• The system divides fingerprints into 3 basic pattern types: arches, loops, & whorls.


• A fourth type listed in some books – composites, also known as “accidentals” – is considered a subtype of whorls: the accidental whorl.

• These three main types are subdivided into eight distinct patterns.


• Arch: Plain or Tented

• Loop: Radial or Ulnar

• Whorl: Plain, Central Pocket Loop, Double Loop, Accidental

• All human fingerprints have friction ridges and these ridges form the basis of all fingerprint patterns.


• Arch Patterns:– Plain Arch: ridges flow from one side of the

pattern to the other with a rise or wave in the center; has a smooth rise & a gentle upward curve; simplest of all fingerprint patterns; generally gives no difficulty being correctly identified.


• Arch Patterns:– Tented Arch: More complex; has either a

central upthrust or well-defined angle; regarded as transitional pattern between arch & loop; example may be seen with “recurving” ridge or other feature common to loop pattern. But, it doesn’t have all 4 of pattern requisites

• Arches represent only about 5% of all pattern types.


• Loop Patterns: a loop has one or more ridges that enter on one side, recurve, & flow back out on same side.

• True loop-4 characteristics: core, approx. center of pattern; delta or triangular area caused by divergence of ridges; at least 1 recurving ridge passing between core & delta; at least 1 ridge count (# of ridges that cross or touch imaginary line between precise core & precise delta).


• Radial Loop & Ulnar Loop: based on ridge flow direction relative to 2 long bones on forearm. Radius–thumb side; Ulna–little finger side. To characterize fingerprint as radial or ulnar loop, you must know which hand it came from. Ridge flows are reversed for left & right hands.

• Loops: 60% of all fingerprints; most common fingerprint pattern


• Whorl patterns:– Plain whorl: has 2 deltas & at least 1 ridge

that makes a complete circuit about the core. Some have concentric circles, ovals, or spiral

– Central pocket loop whorl: complex pattern, perhaps most troublesome to classify; essentially a combination of loop & whorl; has all characteristics of loop with addition of second delta near core & whorl-type ridge or ridges circuiting around the core.


• How to differentiate between plain whorl & central pocket loop whorl: Draw a line between deltas: plain whorl must cross at least 1 whorl-type ridge; in central pocket loop whorl, this cannot happen.

• Double loop whorl consists of 2 separate loop formation, each with its own core & 2 deltas.


• Accidental whorl is a pattern with 2 or more deltas that may not be placed by definition in any of the other classes.

• Whorls represent 35% of all fingerprint patterns.

• Fingerprints intended for classification & filing are recorded on standard 8” x 8” cards.


• These cards have spaces for rolled impressions from each finger (inked & rolled from one side to the other to record the entire pattern) plus spaces for plain impressions (four fingers of each hand are pressed simultaneously, followed by the unrolled thumb print) which serve as checks on the rolled impression so they are recorded in correct sequence.


• Top of card, fingerprint classification & name are recorded. On reverse, portrait parle (“word picture”) of the subject: height, weight, eye color, hair color, scars, etc. & a place for full-face & profile photos. Space for a “criminal history” is usually included on cards recording fingerprints of felons.


• After prints are recorded & information put on card, 1st stage of classification begins called blocking out the set of prints by placing in space below each rolled impression a letter/symbol corresponding to its pattern type.

• All whorls are marked W & ulnar loops are signified by \ for right hand & / for left hand


• For index fingers: A for plain arch, T for tented arch, R for radial loop.

• For all other fingers the same symbols are used but in lowercase a, t, & r.

• Next ridge counts of all loop patterns are written in upper right corners of blocks.


• Finally, each whorl-type pattern is given a ridge trace from lower left side of left delta to right delta dropping to a lower ridge anytime the ridge ends or forks. If trace ends within 1 or 2 ridges of right delta, a meeting whorl is indicated, otherwise it is designated as inner whorl or outer whorl depending on whether trace ridge passes inside or outside the right delta.


• The symbol for appropriate ridge tracing – I, M, or O – is written in upper right-hand corner of each finger block containing a whorl-type pattern to complete blocking-out process.

• Formula for classifying fingerprints may be composed of 7 possible divisions: primary, secondary, subsecondary, major divisions, second subsecondary, final & key.


• Positions in completed classification line are as shown below: Right hand on top of line, left hand below the line

Second

Subsecondary

Classification

Key Major Primary Secondary Subsecondary Final

Divisions Classification Classification Classification


• Note some elements extend above & below the line. Second subsecondary classification, as its position indicates, is optional, used when a group of fingerprints becomes so large that it needs further subdivision.

• Key is the ridge count of the first loop. For the major divisions, ridge counts of thumb are used.


• Anything over 22 ridges is termed large.• Primary classification, whorls are recorded• Secondary classification represents the

patterns of index fingers.• Subsecondary classification is based on

the 3 middle fingers of each hands with whorls being designated I, M, or O & loops depending on small or large ridge counts being represented as I or O.


• Final classification records ridge count of the right little finger with provisions for that print being a pattern other than a loop.

• Such as classification system permits fingerprints to be filed & subsequently retrieved.

• Primary classification alone permits fingerprint cards to be divided into 1,024 groups.


• Classification of “Scarface” Al Capone

29 L 1 U IOI 6

L 1 U IOI

Remember right hand on top of line & left hand on bottom of line


• Key for right thumb is 29, over 22 ridges so Capone gets L/L, devoid of any whorl-type patterns so assigned a simple 1/1 for primary classification, index fingers ulnar loops so U/U for secondary classification, IOI/IOI for three middle fingers as sub-secondary classification, ridge count on right little finger is 6 for final classification. Second subsecondary classification omitted


• In 1933, the FBI addressed the longtime problem of being limited to searching files of known suspects.

• Inauguration of a single-fingerprint file using modifications of a method developed by former Scotland yard Chief Inspector Harry Battley.


• The method utilized a special reticule, half of which had a series of concentric circles that were used to define specific areas of scrutiny. Some pattern types were sub-divided (arches into 5 categories) & ridge counts for whorls were added.

• Additional work multiplied tenfold the work for classificating fingerprints.


• As a practical matter, files were kept only for certain notorious criminals, repeat felons, & those in certain categories such as bank robbers & kidnappers.

• Since 1970, computer technology has made it possible to automate the process of fingerprint searching with the automated fingerprint identification systems (AFIS).


• A serial killer in Los Angeles with 15 murders was identified in about 20 minutes after AFIS was brought into service.

• This would have taken about 67 years to manually search through the fingerprint files that AFIS did in under half an hour.

Identification of Fingerprints

• Method of comparison of fingerprints is to use the ridge characteristics or minutiae to individualize the print, establishing the individuality or uniqueness of it.

• One should speak of identifying a marking as a fingerprint but of individualizing a fingerprint as that belonging to a particular person.


• Ridge characteristics or minutiae used to individualize a fingerprint include those used in AFIS.

• Ridge ending – termination point of a friction ridge (end of friction ridge)

• Bifurcation – branching or forking of a ridge into two ridges


• Ridge dot: ridge feature that resembles a period & is only about as long as it is wide.

• Enclosure: ridge characteristic resembling eyelet caused by bifurcation legs coming together again to form a single ridge.

• Short ridge: one whose terminal (end) points are very close together.


• Trifurcation: branching into 3 bridges

• Bridge: or bar linking two ridges

• Creases: short white lines crossing ridges, not considered minutiae because they are impermanent features (not permanent)

• Scar: may be utilized as such for purpose of comparing two prints


• To actually make a comparison, expert looks for 4 elements to match other print so individualization may be declared.

• 1. Likeness of pattern – two prints must have a likeness of pattern types – arches, loops, etc.

• 2. Qualitative likeness of ridge minutiae – ridge endings must match such as enclosures, bifurcations, etc.


• 3. Quantitative likeness of ridge minutiae – sufficient # of ridge details present for individualization to be declared.

• 4. Likeness of location of minutiae – friction ridge details must be in same relative position, same relative directions & distance from each other & same # of ridges between them in both fingerprints


• There must be no unexplained differences between prints

• Ten to twelve characteristics would generally seem reasonable number in most cases, fewer if points of comparison are particularly distinctive

• If pores in ridges are visible, science of poroscopy may be applied


• Pores are also different from person to person; are permanent & may serve as basis for a positive individualization of one print with another

• Comparator – imaging device placing two greatly enlarged images side by side on an illuminated viewing screen.


• Modern electronic imaging technology using digital photography can also provide nearly instant enlargements of fingerprints for comparative purposes

• For courtroom presentation, the known file print & the questioned latent print are compared side by side in greatly enlarged form.


• Standard method of demonstrating similarity is to draw fine line from each ridge characteristic to white space surrounding the print & give each such point its own number.

• Placement of lines & #s should be as similar as possible on both prints. Usually #s & names of features they represent are listed on exhibit to avoid confusion


• Footprints & palmprints are just as unique as fingerprints & can be used as evidence

• Any area of the inner surface of the hands or feet contains friction ridges and patterns that are just as effective for comparison as fingerprints.

• Only drawback is difficulty of recording and classifying such impressions

Processing and Recovery

• Fingerprints may be recovered from a crime scene in several forms. It is usual to list three types of prints discussed presently, but a fourth special type might be considered as part of a gruesome category such as dismembered fingers or partial tears or dismemberments or even parts of an ear


• Plastic fingerprints: those impressed into some substance such as wax, soap, putty or even dust; 3-D depressions made by friction ridges

• Visible prints: those left by fingers that have been coated with some colored substance such as blood, grease, paint, dirt or ink


• Latent fingerprints: “lie hidden” or are relatively invisible & need some form of processing or developing.

• Plastic & visible fingerprints may easily be photographed, but latent prints require careful handling. They are of a “delicate nature”.


• Surface must be able to retain the print without absorbing & spreading it

• Hard, glossy objects (i.e. glass & enamel painted walls/doors) present ideal surfaces

• Dirty surfaces & absorbent materials do not readily bear prints

• Fingerprint must be deposited with right amount of pressure


• Object must not be touched with an excess of pressure. This tends to spread the print.

• Person’s fingers must have certain degree of moisture or should have some body grease on ridges.

• When all these requirements are fulfilled a god latent fingerprint is deposited.


• Thin film of latent fingerprint contains substances - predominantly perspiration, secreted by pores in friction ridges, &/or body oils acquired by contact with other parts of the body notably the hair and face

• Perspiration made up of moisture, salt, amino acids, dead epidermal cells, and various foreign substances


• Decision regarding what treatment should be used to develop a latent print depends largely on the surface on which it lies, experience with the substances in the prints and the technology available.

• Searching for fingerprints is conducted by specially trained personnel


• Wearing light cloth gloves while collecting evidence is recommended although some experts use disposable latex gloves.

• One authoritative source recommends against gloves entirely since they invite carelessness that may destroy prints or leave glove prints that mislead others.


• Objects should be handled minimally & by edges or by surfaces unreceptive to prints

• Fingerprint expert should be given priority access to objects such as firearms & documents over other criminalists

• Any articles removed from scene must be correctly labeled & carefully transported to prevent destruction of prints


• In looking for fingerprints, flashlight & magnifying glass represent standard equipment.

• Beam of flashlight at an acute angle to surface may help reveal latent impressions.

• Examining surface from various angles may accomplish same purpose


• When a plastic or visible fingerprint is discovered, it should be photographed in situ, as should a latent impression after it is developed

• Approach for latent prints discovered on nonporous surfaces begins with visual search & if necessary search with more sophisticated light sources: argon laser beam causing latent print to fluoresce


• Using lasers to detect latent prints is clean -no pretreatment of specimen is required -no alteration of evidence. Therefore it is used 1st & conventional methods used 2nd

• RUVIS: Reflected Ultraviolet Imaging System makes use of wavelengths beyond those of visible light; can reveal latent impressions that might otherwise go undetected


• Following laser detection on nonporous surface, next step for relatively small objects is to develop print using cyanoacrylate vapor – a.k.a. “Superglue”

• Technique was brought from Japan to US by Ed German & Paul Norkus of U.S. Army crime lab & improved in 1982 by Frank Kendall by adding sodium hydroxide


• Fuming process is carried out in an airtight tank.

• Instead of fuming or in addition to it, fingerprint expert may use a brush to apply fingerprint powders.

• Standard powders are lampblack for use on light-colored surfaces & titanium oxide for dark surfaces.


• Colored powders such as dragon’s blood are used for certain special situations.

• Alternatively, a magnetic-sensitive powder is applied with magnet - Magna Brush. Since no brush bristles, less chance print will be damaged.

• Special fluorescent powders used with laser or other forensic light sources


• Reason for using first the forensic light sources, then chemical fuming, & finally dusting with powders is to be as non-destructive as possible.

• Powder may result in smudging or over-processing the print & once it is used, other procedures are generally precluded


• After a print is developed by powdering, it may be lifted with special transparent tape & then protected with a stiff, transparent cover

• Since lifting process is somewhat risky & may damage or distort print, impression should be photographed before lifting tape is applied


• Porous surfaces such as paper, cardboard & unpainted wood present more difficulty.

• With such surfaces, powders should be avoided since they tend to adhere to the background surface as well as the print.

• Following visual & fluorescent examination, you can use chemical treatment with ninhydrin to develop latent impressions that might be present


• Other techniques used for porous materials include application of a solution of silver nitrate or other silver based solution called “physical developer”.

• For developing prints on wet surface, a material called “small particle reagent” may be used


• One of most difficult surfaces to develop fingerprints on (yet one of the most useful as probative evidence) is human skin

• The fact that murderers frequently grab their victims makes it desirable for homicide investigators to develop identifiable fingerprints from the corpse’s skin


• Problem developing skin fingerprints is they contain same substances as human skin does.

• Most effective procedure is cyanoacrylate fuming technique & applying magnetic fingerprint powder


• Because of condensation on refrigerated bodies, it is recommended that prints be recovered before the body is refrigerated if possible. Otherwise, the process should be delayed while any moisture evaporates

• Enhancing fingerprints can be done using programs such as Adobe Photoshop to improve sharpness & contrast.

Case Study: Aileen WuornosFemale Serial Killer

• Gives evidentiary value to fingerprints.

• Female lesbian prostitute who shot her victims whether or not they picked her up as a prostitute or not

• Watch A & E movie “Death Row Prostitute” and answer video quiz questions.

Fingerprints History Earliest recognition of uniqueness of fingerprints & their suitability for...

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