Friction Ridge Examination Chapter 19

Friction Ridge Examination Chapter 19
Physical Sciences Friction Ridge Examination Chapter 19 ©2010 Elsevier, Inc.

Objectives  Describe the history of fingerprinting and its function in the United States  Understand what friction ridges are and how the friction ridge patterns can be visualized  Recognize how fingerprints are collected, preserved for analysis, and used as an identification tool  Relate the longevity of friction ridge prints and the usefulness of elimination prints

THE NATURAL BORN CRIMINAL
Lombroso’s theory of the criminal man influenced criminal identification and criminology Criminals were said to be identified by unattractive characteristics Large jaws, large faces, long arms, low and narrow foreheads, large ears, excess hair, darker skin, insensitivity to pain and inability to blush Racial stereotyping ©2010 Elsevier, Inc.

THE NATURAL BORN CRIMINAL
Lombroso’s theory sparked a search for real, measurable traits that would identify criminals Bertillion devised a complex system of anthropometric measurements, photographs and descriptions Called Bertillionage Used to quantify the body Complicated, involved process Difficult to standardize and replicate Imprecise objective definitions Bengal, India office eventually dropped use of Bertillionage, except fingerprint component ©2010 Elsevier, Inc.

FINGERPRINTING IN THE UNITED STATES
First known systematic use of fingerprint identification in U.S. occurred in 1902 in New York City New York Civil Service Commission scandal New York State Prison Department New York State Hospital United States Penitentiary in Leavenworth, Kansas followed suite and developed a fingerprint bureau 1904 World’s Fair brought fingerprint technique more notoriety ©2010 Elsevier, Inc.

FINGERPRINTING IN THE UNITED STATES
First U.S. criminal conviction using fingerprint evidence occurred in Chicago in the case of Thomas Jennings International Association for Identification was formed in 1915 The Finger Print Instructor by Kuhne was published in 1916 Identification Division of FBI was established in 1924 as a national repository and clearinghouse for fingerprint records Civil Identification Section was developed in 1933 Identification Division was renamed the Criminal Justice Information Services Division in 1992 ©2010 Elsevier, Inc.

WHAT ARE FRICTION RIDGES?
Friction ridges appear on palms, soles, and the ends of fingers and toes All primates have arboreal evolutionary heritage Ridges provide friction between the grasping mechanism and whatever it grasps ©2010 Elsevier, Inc.

Friction ridges develop in utero Begin forming in the 9th or 10th week of fetal development Primary friction ridges develop deep in the dermal layer of the skin At about 14 weeks of gestation, sweat glands and ducts begin to form, proliferating from the primary friction ridges Primary friction ridges proliferate until about 15th or 17th weeks of gestation Secondary friction ridges appear after proliferation of primary friction ridges stop Secondary friction ridges develop from 17th to 24th weeks of gestation ©2010 Elsevier, Inc.

Interface between epidermis and dermis provides template for configuration of the friction ridges on the surface Numerous factors affect patterning and arrangement of friction ridges including: Genetics Environmental factors Drugs Disease Shape of volar pad Friction ridges remain the same throughout life Scarring or other trauma to the epidermal-dermal margin may alter the friction ridge area ©2010 Elsevier, Inc.

What’s a Friction Ridge Print Made of?
A friction ridge print is representation of a friction ridge pattern in some medium Patent prints are visible with the unaided eye Some transferable material on the ridge pattern Ridge pattern left in soft substrate with “memory” ©2010 Elsevier, Inc.

What’s a Friction Ridge Print Made of?
Latent prints require some sort of assistance to make them visible Composed of the sweat and oils of the body that are transferred from the ridge pattern to some substrate where they persist for some time Most familiar visualizing techniques uses fingerprint powder Colored, fluorescent or magnetic materials that are finely ground Brushed lightly over a suspected print to produce contrast between background and print ©2010 Elsevier, Inc.

Collecting Prints at Crime Scene
Friction ridge prints can be left on a wide variety of surfaces and may persist for quite some time Can be obtained from a variety of surfaces including: glass, painted surfaces, plastics, ceramics, paper and books ©2010 Elsevier, Inc.

FRICTION RIDGE PATTERN VISUALIZATION TECHNIQUES
Visualization techniques may be physical, chemical or optical enhancements Fingerprint powders create contrast between ridge pattern and background May be black, white and other colors Color used is determine by background ©2010 Elsevier, Inc.

FRICTION RIDGE PATTERN VISUALIZATION TECHNIQUES
Fingerprint powders Applied with a soft fiberglass brush that has long, very fine bristles Print is lifted with frosted or clear tape for mounting on a contrasting background card Information about the print, where, when and how it was lifted and by whom, is recorded on card Identifier for chain of custody is also recorded Three main types of lasers used to detect fingerprints are: argon, copper vapor, and Nd:YAG ©2010 Elsevier, Inc.

PRESERVING PRINTS FOR ANALYSIS
Friction ridge prints should be photographed when they are found at the crime scene or at the laboratory Requires skill in various methods of lighting, exposure, filters, and latent print enhancement Final image should be a 1:1 print to facilitate the eventual comparison If surface is difficult to process, it should be submitted to the laboratory for examination ©2010 Elsevier, Inc.

PRINCIPLES OF FRICTION RIDGE ANALYSIS
Galton was the first to scientifically study fingerprints Developed classification system for common fingerprint patterns that is still is use today Friction ridges are considered unique Galton attempted to calculate the likelihood of finding two friction ridge patterns that are the same All similar calculations indicate that the probability of any one fingerprint is between and 1.2 × 10−80 Considered unique by the vast majority of forensic scientists and the courts More similarities between two prints leads to a lower probability of false positives ©2010 Elsevier, Inc.

Friction ridges are studied for the kind, number and location of various ridge characteristics or minutiae Arrangement of characteristics create one-of-a-kind pattern Careful point-by-point study determines if enough significant minutiae present in the known print are present in the questioned print ©2010 Elsevier, Inc.

Majority of prints are identified, resolved and compared are partial prints Only a portion of the complete print pattern is represented Scientist must determine if sufficient information is present to make a proper comparison Prints may be unidentifiable due to smudging, graininess, or size Dependent upon scientist’s experience, visual acuity, and judgment ©2010 Elsevier, Inc.

Forensic scientists debate how many points of comparison are necessary and sufficient to reach a conclusion of identification Point counting standard dictated how many points of comparison were required before a positive conclusion could be reached Varied from 8 to 20 No statistical basis for such numbers Most agencies use a “no-point” standard Threshold is one of a sufficient number of characteristics necessary to make a conclusion of identification, however many that might be Experience and judgment are central to the process of a quality examination Requires proper training and practical experience Experts must be able to articulate and support their findings ©2010 Elsevier, Inc.

Latent Prints Forensic Science T. Trimpe

Latent prints are impressions left by friction ridge skin on a surface, such as a tool handle, glass, door, etc. Prints may be collected by revealing them with a dusting of black powder and then lifted with a piece of clear tape. 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.

Click the icon to view the Crime 360 Super Glue Video
Some investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces. Magnetic powder can also be used to reveal latent prints. This type of powder works better on shiny surfaces or plastic baggies or containers. The cyanoacrylate fuming method (often called the super glue method) is a procedure that is used to develop latent fingerprints on a variety of objects. 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. Click the icon to view the Crime 360 Super Glue Video Top Left: Bottom Left: Bottom Right:

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 isn’t easy to clean up. Don’t dust anything without permission!

Clean Up 1 – 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 weren’t 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!

8th Grade Forensic Science
Fingerprints 8th Grade Forensic Science T. Trimpe

Fingerprint Principles
According to criminal investigators, fingerprints follow 3 fundamental principles: A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern. A fingerprint pattern will remain unchanged for the life of an individual; however, the print itself may change due to permanent scars and skin diseases. Fingerprints have general characteristic ridge patterns that allow them to be systematically identified.

Fingerprint Classes There are 3 specific classes for all fingerprints based upon their visual pattern: arches, loops, and whorls. Each group is divided into smaller groups as seen in the lists below. Arch Plain arch Tented arch Loop Radial Loop Ulnar loop Whorl Plain whorl Central pocket whorl Double loop whorl Accidentical

60% of people have loops, 35% have whorls,
Interesting Info Fingerprint Factoid: 60% of people have loops, 35% have whorls, and 5% have arches Did you know? Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting “dactylograms”, otherwise known as fingerprints. ADD TO NOTES

Arches Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present. Tented Arches Similar to the plain arch, but has a spike in the center. Spike or “tent” Plain Arch Ridges enter on one side and exit on the other side.

Loops Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones. Radial Loop (Right Thumb) Loop opens toward the left or the radial bone. Ulnar Loop (Right Thumb) Loop opens toward right or the ulna bone. Delta 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.

Whorls Whorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental. Central Pocket Whorl Plain Whorl 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. If none of the center core touches the line, it is a central pocket whorl.

Whorls – Part 2 Double Loop Whorl
Double loop whorls are made up of any two loops combined into one print. Delta Accidental Whorl Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories.

Identify each fingerprint pattern.
? A B Right Hand Left Hand C Right Hand E D Right Hand Left Hand

It’s time to make some prints!
Avoid Partial Prints GOOD PRINT Get as much of the top part of your finger as possible!

Directions 1st – 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 “My Prints” 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 pattern’s name.

Classifying Fingerprints
General patterns of friction ridges allow for their classification and organization Fingerprints are divided into three classes: loops, arches, and whorls Relative appearance of loops is 60-65%, whorls 30-35% and arches 5% ©2010 Elsevier, Inc.

Loops have one or more ridges entering from one side of the print, curving back on themselves and exiting the fingertip on the same side A loop that enters and exits on the side of the finger toward the little finger is called an ulnar loop A loop that enters and exits on the side toward the thumb is called a radial loop Loops are surrounded by two diverging ridges called type lines The point of divergence is called the delta The central portion of the loop is called the core ©2010 Elsevier, Inc.

Arches are the rarest of the three main classes or patterns A plain arch has ridges that enter from one side of the finger, gradually rise to a rounded peak and exit the other side A tented arch is a pronounced, sharp peak Arches do not have type lines, cores or deltas ©2010 Elsevier, Inc.

Whorls are subdivided into several classes A plain whorl is located between two deltas of the whorl pattern and has a minimum of one ridge that is continuous around the pattern A central pocket loop is not located between two deltas of the whorl pattern and has a minimum of one ridge that is continuous around the pattern A double loop is made up of two loops that swirl around each other An accidental is a pattern that combines two or more patterns, excluding the plain arch, and/or does not clearly meet the criteria for any of the other patterns All whorls have type lines and at least two deltas ©2010 Elsevier, Inc.

Classification Based on Henry system
Modern fingerprint classification consists of a primary classification that encodes fingerprint pattern information into two numbers Arches and loops are given a value of zero Whorls are given a number depending on which finger they appear Values are summed and the resulting primary classification is displayed like a fraction Considered class evidence Comparison of minutiae and higher level details is only method for fingerprint identification Drawbacks include: Rarely are full sets of prints found at a crime scene Time consuming Error prone ©2010 Elsevier, Inc.

HOW LONG DO FRICTION RIDGE PRINTS LAST?
Plastic prints remain as long as the impressed material is structurally intact Prints left in a medium, such as blood or dust, are fragile and do not last long Latent prints, in a proper environment, can last for years Age of prints is almost impossible to determine ©2010 Elsevier, Inc.

ELIMINATION PRINTS Elimination prints can eliminate individuals from an investigation’s focus, demonstrate proper scientific mindset, create confidence in the mind of the trier-of-fact Displaying what is and what is not a match clarify process of identification and comparison ©2010 Elsevier, Inc.

Automated Fingerprint Identification Systems (AFIS)
Process of capturing, storing, searching and retrieving fingerprints via computer is now a standard occurrence Automated fingerprint identification systems (AFIS) are computerized databases of digitized fingerprints that are searchable through software Integrated Automated Fingerprint Identification System, IAFIS, was developed to ease the exchange of information between systems ©2010 Elsevier, Inc.

Capabilities include: Enhance an image to improve its quality Compare crime scene fingerprints against known 10-print records retrieved from the database Search crime scene fingerprints against known fingerprints when no suspects have been developed Automatically search the prints of an arrestee against a database of unsolved cases ©2010 Elsevier, Inc.

IDENTIFICATION Final identification decision in fingerprint comparison is reached when sufficient quality and quantity of Level 1, 2, and 3 friction ridge details are present Level 1 detail includes the general ridge flow and pattern configuration Not sufficient for identification Information may include orientation, core and delta location, and distinction of finger versus palm ©2010 Elsevier, Inc.

IDENTIFICATION Level 2 detail includes formations, defined as ridge endings, bifurcations, dots or combinations of these features Sufficient for identification Relationship of these features enables individualization Level 3 detail includes all attributes of a ridge, such as ridge path deviation, width, shape, pores, edge contour, incipient ridges, breaks, creases, scars, and other permanent minutiae ©2010 Elsevier, Inc.

8th Grade Forensic Science
Ridgeology A Closer Look at Fingerprints 8th Grade Forensic Science Image from ftp://sequoyah.nist.gov/pub/nist_internal_reports/ir_6534.pdf T. Trimpe

Ridgeology: The study of the uniqueness of friction ridge structures and their use for personal identification.1 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 as well as the minutiae points, which are points where the ridge structure changes. 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? 1Introduction to Basic Ridgeology by David Ashbaugh, May Image from

Automated Fingerprint Identification System (AFIS)
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) 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.

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

Ridge Characteristics
Crossover Core Bifurcation (fork) Ridge ending Island Delta Pore Scar EXAMPLE

How many ridge characteristics can you identify in this fingerprint?

Try It! 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. 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:

How do our fingerprint patterns compare to the expected averages?
Fingerprint Analysis How do our fingerprint patterns compare to the expected averages?

How do our results compare to the averages?
Let’s determine the rate of occurrence for our fingerprint patterns ... Pattern # Total Prints % Arch Loop Whorl How do our results compare to the averages? 60% - Loops % - Whorls % - Arches __% - Loops __% - Whorls __% - Arches Write a paragraph on your worksheet that summarizes our results.

Let’s determine the rate of occurrence to compare males vs. females.
Pattern # Male # Female Total Prints % Arch Loop Whorl Which 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?

Friction Ridge Examination Chapter 19

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