Forensic Fingerprint Analysis

Forensic Fingerprint Analysis

History of Fingerprints1788 - Johann Mayer noted that the arrangement of skin ridges is never duplicated in two persons. He was probably the first scientist to recognize this fact.

1880 Henry Fauldworking in Japan publishes fingerprint identify after case where print was left on whitewashed wallRejected for Bertillon system for 20 years then adopted

1892 Francis Galtonassigned fingerprints into 3 typesLoops, Whorls, and Arches

3 Fundamental Principles of FingerprintsA fingerprint is an individual characteristic. No 2 people have been found to have identical ridge characteristic

1 x 1020 chance of 2 people having identical ridge characteristicsThats 1 in 100,000,000,000,000,000,000!A fingerprint remains unchanged during an individuals lifetime - each print is composed of valleys and ridges- The ridges are believed to help with grip- Each ridge has multiple sweat pores that lead to sweat glands

People have tried to change their printsJohn Dillinger (public enemy #1)

Fingerprints have general ridge patterns that permit them to be systematically classified

Fingerprint ClassesThere are 3 specific classes for all fingerprints based upon their visual pattern: arches, loops, and whorls.

Each group is divided into smaller groups ArchLoopWhorl

9Arches, Loops, Whorls

Directions1st Roll the pad portion of your thumb over the ink pad from the left side of your thumb to the right. You do not have to push down really hard!

2nd Roll the pad portion of your thumb from the left side of your thumb to the right in the correct box on your paper to make a thumbprint. 3rd Continue this process to make a fingerprint of all ten fingers on the Data Table A worksheet.4th Use your notes and a magnifying lens to help you figure out what type of pattern is found in each of your fingerprints. Label each one with the patterns name.Its time to makesome prints!

Avoid Partial PrintsGOOD PRINTGet as much of the top part of your finger as possible!12How do our fingerprint patterns compare to the expected averages?

Fingerprint AnalysisTable C Right Hand Left Hand Loop Whorl ArchLets determine the rate of occurrence for our fingerprint patterns ...Pattern#Total Prints%ArchLoopWhorlHow do our results compare to the averages?60% - Loops 35% - Whorls 5 % - Arches __% - Loops __% - Whorls __% - ArchesWrite a paragraph on your worksheet that summarizes our results.

Lets determine the rate of occurrence to compare males vs. females.Pattern# Male# FemaleTotal Prints%ArchLoopWhorlWhich pattern is most common pattern among the males in this class?Which is most common pattern among the females?How do the averages for each sex compare to the expected averages? Characteristics of Fingerprints Forensic examiners look for the presence of core and deltas.The core is the center of a loop or whorlThe delta is a triangular region where ridges change directionsA ridge count is another characteristic used to distinguish one fingerprint from another.Draw an imaginary line from the center of the core to the edge of the delta

Forensic Science: Fundamentals & Investigations, Chapter 6 18

Characteristics of Fingerprints Forensic examiners look for the presence of a core (the center of a whorl or loop) and deltas (triangular regions near a loop). A ridge count is another characteristic that distinguishes one fingerprint from another. The count is made from the center of the core to the edge of the delta.

Interesting InfoDid you know?Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting dactyl grams, otherwise known as fingerprints.Fingerprint Factoid: 60% of people have loops, 35% have whorls, and 5% have archesADD TO NOTES19ArchesArches are the simplest type of fingerprints Formed by ridges that enter on one side of the print and exit on the other. No deltas are present.Plain ArchRidges enter on one side and exit on the other side.

Tented Arches Similar to the plain arch, but has a spike in the center.Spike or tent20LoopsLoops must have one or more ridges that enter and leave on the same side.Have one delta These patterns are named for their positions related to the radius and ulna bones.Delta

2122

Ulnar loopRadial loopTo characterize a fingerprint as a radial or ulnar loop, one must know from which hand it came.

Radial LoopLoop opens toward right or the ulna bone. (toward Pinkie finger)

Ulnar LoopLoop opens toward the left or the radial bone.(thumb)NOTE: On the left hand, a loop that opens to the left would be an ulnar loop, while one that opens to the right would be a radial loop. WhorlsWhorls have at least one ridge that makes (or tends to make) a complete circuit. (4 types)Have at least two deltas. If a print has more than two deltas, it is most likely an accidental.Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. 2)If none of the center core touches the line, it is a central pocket whorl.

Plain WhorlCentral Pocket Whorl24Whorls Part 2

Accidental WhorlAccidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories. Double Loop WhorlDouble loop whorls are made up of any two loops combined into one print.

DeltaDelta2526

Central WhorlPlain WhorlAccidental WhorlDouble Loop WhorlIdentify each fingerprint pattern.?

CRight Hand

ALeft Hand

ELeft Hand

BRight Hand

DRight HandPLAIN WHORLDouble loop WhorlPLAIN ARCHULNAR LOOPTENTED ARCH27Classification of Prints1st system: Henry system but could only handle 100,000 printsToday IAFIS has over 66 million (66,000,000) sets of printsToday use FBI system, very similar to Henry systemAll prints will fit in 1 of 1,024 different groupsFBI SystemPair up fingers in 5 fractions:R. Index R. RingL. ThumbL. MiddleL. Little +1 R. Thumb R. MiddleR. LittleL. IndexL. Ring +1Now look for presence of a whorlIf on the first pair = 16If on 2nd pair = 83rd pair = 44th pair = 25 pair = 1Add up 1 to numerator and denominator and all togetherExample of FBI systemIf whorls were found on right index, right middle fingers 16 + 0 + 0 + 0 + 0 + 1 0 + 8 + 0 + 0 + 0 + 1* 25% of population has a 1:1 ratio=17/9Ridgeology: The study of the uniqueness of friction ridge structures and their use for personal identification.1 The koala is one of the few mammals (other than primates) that has fingerprints. In fact, koala fingerprints are remarkably similar to human fingerprints; even with an electron microscope, it can be quite difficult to distinguish between the two.

Did you know?As we have learned in our first lesson, a fingerprint is made of a series of ridges and valleys on the surface of the finger. The uniqueness of a fingerprint can be determined by the pattern of ridges and valleys

Fingerprint Identification

When minutiae on two different prints match, these are called points of similarity or points of identification. At this point there is no international standard for the number of points of identification required for a match between two fingerprints. However, the United Kingdom requires a minimum sixteen points while Australia requires twelve.

Automated Fingerprint Identification System (AFIS)http://www.fdle.state.fl.us/CrimeLab/images/fingerrint%20comparison%20for%20afis.jpg

AFIS is a computerized system capable of reading, classifying, matching, and storing fingerprints for criminal justice agencies.Quality latent fingerprints are entered into the AFIS for a search for possible matches against the state maintained databases for fingerprint records to help establish the identity of unknown deceased persons or suspects in a criminal case. 33AFIS CLOSE UP

Automated Fingerprint Identification System :A network that scans crime scene fingerprints and compares them with millions of prints collected by law enforcement agencies around the world.LivescanDont use ink much anymore, but scan directly into the computer

35MinutiaeEach individual has unique fingerprints. A fingerprint is defined by the uniqueness of the local ridge characteristics and their relationships.

Minutiae points (aka Galtons details) are the local ridge characteristics.

Identification points consist of bifurcations, ending ridges, dots, ridges and islands.

A single rolled fingerprint may have as many as 100 or more identification points that can be used in order to identify the individual.

Island

Dot

Bifurcation

Ridge endingRidge Characteristics

Use these characteristics as points of identification when comparing fingerprint samples. The more points you can find in common, the better the match!www.fbi.gov37Minutiae Patterns

www.fbi.gov38Minutiae Patterns

Ridge Characteristics

CrossoverCoreBifurcation (fork)Ridge endingIslandDeltaPoreScarEXAMPLEhttp://www.dkfz.de/tbi/projects/bmcv/images/iu_it246_04s_fingerprint1.jpg

How many ridge characteristics can you identify in this fingerprint?

1 Blow up your balloon about halfway and twist the end to keep the air from coming out. Do not tie it off! 2 Use an ink pad to make a print with all of your fingers and label each one with a permanent marker. Write your name on the balloon as well. 3 Blow up the balloon to full size and tie the end. 4 Analyze the fingerprints to find several ridge structures that we have discussed. Use a highlighter to mark these structures on your My Prints worksheet. Try It!Think About It!

Which ridge structures were most common in your fingerprints?

Which ridge structures were most common in your group?

Were there any structures that were not found in any of the fingerprints? Balloon Fingerprint Activity: http://www.msichicago.org/fileadmin/Education/learninglabs/lab_downloads/fingerprint_analysis.pdf3 types of printsVisible printsPrints seen with naked eye in oil (blood, paint, grease, ink)Plastic PrintsPrint impression left on putty, wax, soap, or dust

Latent prints are impressions left by friction ridge skin on a surface, such as a tool handle, glass, door, etc. that are invisible to the naked eye.

Prints may be collected by revealing them with a dusting of black fingerprint powder.

Did you know? Camel hair is the most common animal hair used to make fingerprint brushes. Now many brushes (like the one above) are made out of fiberglass.

Powdering TechniquesAlways wear glovesHold brush lightly between index finger and thumbApply powder with tips of strands of brushBrush WITH the grain of the ridges

Use fiberglass brushes for graphite powderThe cyanoacrylate fuming method (often called the super glue method) is a procedure that is used to develop latent fingerprints on a variety of objects.

Bottom Right: http://www.forensicsrus.com/images/SupergluePrint.jpgMagnetic powder can also be used to reveal latent prints. This type of powder works better on shiny surfaces or plastic baggies or containers.

Top Left: http://www.stapletonandassociates.com/images/MagPowder.jpgBottom Left: http://www.ok.gov/osbi/images/ninhydrin%20print.jpgSome investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces.RUVIS Reflected Ultraviolet Imaging System

Ninhydrin is a chemical that bonds with the amino acids in fingerprints and will produce a blue or purple color. It is used to lift prints from surfaces such as paper and cardboard.

Iodine FumingIodine sublimes and sticks to oils

Silver NitrateSticks to salt in perspiration. Good for porous surfaces or have even been wet at one time

48IF MORE THAN ONE METHOD IS USED...If more than one method is used to develop prints, the order in which the techniques are used is important. The following order should be used to develop fingerprints:

This is the procedure used for optimal visualization because Iodine fuming is not permanent.

If Ninhydrin fails, silver nitrate can be used but it will wash away all the fatty oils and proteins from the surface.

Superglue fuming, if used, must be used last.(1)Iodine fuming(2)Ninhydrin(3)Silver nitrate(4)SupergluefumingPreservation of PrintsAlways take a digital picture of printIf small enough object, wrap in cellophane to preserve printOr use piece of adhesive (scotch tape) and then stick to contracting piece of cardboard (mounting card)

Photographing Prints Photograph latent print life size 1:1If not 1:1 fill the frameUse macro lensInclude identification tag with scaleMaintain photo log

Directions:1 - Cover your table with white butcher paper or newspaper. You must dust everything on the paper!2 - Get a lifting kit from your teacher that contains black powder, brushes, and clear tape. 3 - Press the pad of your right thumb on a CD or glass slide to make a print. Place on the paper covering your table.4 Dip a brush lightly into the container of black powder and then tap off the extra on the lid. You only need a very small amount of powder to dust the print.5 Hold the brush over the print and rotate it between your thumb and fingers. Use the brush to remove any extra powder.6 - Use a small piece of clear tape to lift the print and place it in the box on your worksheet.CAUTION: The black powder will be messy and isnt easy to clean up. Dont dust anything without permission!Clean Up1 Clean off the CDs or glass slides and put them back in the kit with the brushes and tape. 2 Have someone help you fold the paper in half and tap it to return the extra black powder to the container. 3 Put the black powder in the box and have it checked in by your teacher. 4 Get a towel and dry wash the table especially the edges that werent covered with paper. 5 Get a wet towel to wash off the table and then wipe it with some dry towels. Keep cleaning until all the black powder is off the table!BingoAccidental WhorlCentral Pocket WhorlCynoacrylateDeltaDouble loop WhorlDusting for PrintsFrancis GaltonHenry NumberIAFISIodine FumingLatentMinutae

NinhydrinPlain ArchPlain WhorlPlasticRadial LoopRUVISTented ArchUlnar LoopVisible10%30%60%