T Trimpe 2006 Bertino A Brief

T. Trimpe 2006 & Bertino

A Brief History • Early 1800 s—fingerprint patterns first discussed • 1892—Francis Galton published book fingerprints used to identify individual people Sir Francis Galton

What Is a Fingerprint? • Ridges of skin that are created when we are still in our mother’s womb. • Remain the same for the rest of our lives • Each of the ridges connect to other ridges, forming a pattern that is unique to all others. • This uniqueness is used in many forensic cases to solve crimes, as some of the most common evidence found at a crime scene are fingerprints.

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

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.

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. Spike or “tent” Plain Arch Ridges enter on one side and exit on the other side. Tented Arches Similar to the plain arch, but has a spike in the center.

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. Delta Ulnar Loop (Right Thumb) Loop opens toward right or the ulna bone. Radial Loop (Right Thumb) Loop opens toward the left or the radial bone. 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 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. Plain Whorl Central Pocket 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 Accidental Whorl Delta Double loop whorls are made up of any two loops combined into one print. 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. Right Hand Left Hand

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. 1 Introduction to Basic Ridgeology by David Ashbaugh, May 1999 Image from http: //www. cs. usyd. edu. au/~irena/minutia. gif

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) 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. http: //www. fdle. state. fl. us/Crime. Lab/images/fingerrint%20 comparison%20 for%20 afis. jpg

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 XA E LE MP Crossover Core Bifurcation (fork) Ridge ending Sca r Island Delta Pore http: //cnx. org/content/m 12574/latest/properties. jpg

How many ridge characteristics can you identify in this fingerprint? http: //www. dkfz. de/tbi/projects/bmcv/images/iu_it 246_04 s_fingerprint 1. jpg

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: http: //www. msichicago. org/fileadmin/Education/learninglabs/lab_downloads/fingerprint_analysis. pdf

Analyzing Prints • The way a suspect print is analyzed is that it’s compared to a print found at a crime scene. If there a certain number of points of minutiae that match, then a match is made. • Minutiae are small details that are breaks in the patterns of the ridges. No two people have the same set of minutiae. Examples of types of minutiae from perso. orange. fr/. . . /types/fingerprint. ht m

Print Types • Latent prints- latent prints are hidden and deposited via the secretions from skin. They are often made visible through a number of different techniques. • Patent prints- highly visible and made from foreign substances such as blood. Since they need no further visualization, they are often just photographed to preserve the evidence. • Plastic prints- Friction ridge impressions deposited in a material that retains the shape such as clay or or melted wax.

Classification Review • Arches • Loops The most commonly found types of fingerprints are whorls, while the least common types are arches. Loops fall somewhere inbetween. • Whorls There is more specific types of classification techniques, and these are just the most basic three. For example, arches can be broken down into plain arches or tented arches, and whorls can be broken down into accidental whorls, or any other number of whorl types.

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

Ten Card Example

Directions 1 st – 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! 2 nd – 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. 3 rd – Continue this process to make a fingerprint of all ten fingers on the “My Prints” worksheet. 4 th –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.

What Are Fingerprints? • All fingers, toes, feet, and palms are covered in small ridges • Ridges help us grip objects • Ridges are arranged in connected units called dermal, or friction, ridges • Fingers accumulate natural secretions and dirt • Fingers leave create prints on objects we touch

Structure of Skin 25

Techniques For Lifting a Print

Dusting • Used on smooth, nonporous materials. • The area is lightly and carefully dusted with either a black or white powder, depending on the contrasting surface. • The dust is lifted with tape and set against a contrasting background. • The print is preserved via photography. Fingerprint dusting in a lab

Iodine Fuming • Suspect material is placed in an enclosed cabinate along with iodine crystals. • The crystals are heated, and will sublimate (turn into a gas vapor). • The vapors cause the prints to visualize. Fingerprint visualized with iodine fuming.

Chemical Treatment • Ninhydrin (triketohydrindene hydrate)this chemical is sprayed onto a porous surface via an aerosol can. Prints begin to visualize an hour or two after application, although the process can be accelerated through heating the print. • Silver nitrate- silver nitrate is sprayed onto the porous surface and left to dry. Then it is exposed to ultraviolet light to visualize the prints. Silver Nitrate spray bottle

Superglue Fuming • Used mainly on non-porous materials. • Superglue is placed on cotton and treated with sodium hydroxide. • Fumes can also be created by heating the glue. • The fumes and the object are contained in a closed chamber for up to six hours. • The fumes adhere to the print, visualizing it. Fuming tank

Fingerprint Forensic FAQs • Can fingerprints be erased? Only temporarily; they will grow back if removed with chemicals • Is fingerprint identification reliable? Yes, but analysts can make mistakes • Can computers perform matches in seconds? No, but the FBI’s Integrated Automated Fingerprint Identification System (IAFIS or AFIS) can provide a match in 2 hours