Unit 4 Fingerprint Identification

Students will explore fingerprint identification Unit 4 Fingerprint Identification

Vocabulary • Latent print • Visible print • Plastic print • Iodine fuming • Super glue fuming • Ninhydrin • Physical developer • Epidermis • Dermis • Keratinocytes • Melanocytes • Merkel’s cells • Langerham’s cells • Papillary Layer • Sebaceous gland • Sudoriferous gland • First Principle • Second Principle • Third Principle • AFIS

DESCRIBE THE BASIC FUNCTIONS OF THE INTEGUMENTARY SYSTEM • Functions of Skin • Protection: Provides a physical barrier between the environment and underlying tissues. Provides protection from bacterial invasion. • Synthesis of Vitamin D: In the presence of ultraviolet radiation (sunlight), the skin synthesizes Vitamin D which is necessary for the absorption of calcium. • Reception of Stimuli: Contains numerous nerve endings and receptors to detect touch, pressure, and pain. • Temperature Regulation: Produces perspiration by the sudoriferous glands (sweat glands) to help maintain normal body temperature • Protection against ultraviolet radiation (melanin).

INDENTIFY THE LAYERS OF THE SKIN AND APPENDAGES • Epidermis-outermost layer of the skin that contains no blood vessels (avascular) and is nourished by diffusion from the dermis. The epidermis prevents most bacteria, viruses, and other foreign substances from entering the body. The epidermis along with the other layers of skin protects the internal organs, muscles, nerves, and blood vessels against trauma. The epidermis contains several layers and has 4 types of cells

INDENTIFY THE LAYERS OF THE SKIN • Keratinocytes- produce keratin, a protein that gives the skin strength, flexibility and waterproofs the skins surface • Melanocytes-produce melanin, the dark pigment that gives the skin color • Merkel’s cells-involved in touch reception • Langerham’s cells- help the immune system by processing antigens (foreign bodies) • The deepest layer of the epidermis is called the stratum basale, where cells divide continuously. As new cells form, old cells are pushed toward the skins surface.

INDENTIFY THE LAYERS OF THE SKIN • Papillary Layer • The papillary layer lies directly beneath the epidermis and connects to the dermis by the papillae (finger-like projections). A double row of papillae in finger pads produces the ridged fingerprints on fingertips. There are similar patterns on the palm of the hand and the soles of the feet. Fingerprints and footprints keep skin from tearing and aid in the gripping of objects.

INDENTIFY THE LAYERS OF THE SKIN • Dermis-the middle layer of skin characterized by a thick layer of fibrous and elastic tissue that gives the skin flexibility and strength. The dermis contains nerve endings, sweat glands, oil glands, hair follicles, and blood vessels.

INDENTIFY THE LAYERS OF THE SKIN • Subcutaneous layer-below the dermis lies a layer of fat that helps insulate the body from heat and cold, provides protective padding, and serves as an energy storage area. Also referred to as the hypodermis.

INDENTIFY THE APPENDAGES OF THE SKIN • Nails • Specialized growth of epidermal tissue. • Help us grasp and manipulate small objects • Sweat (sudoriferous) glands • Sweat is produced by the sudoriferous glands. • Sweat is a mixture of 99% water and 1% salts and fats

INDENTIFY THE APPENDAGES OF THE SKIN • Oil (sebaceous) glands • Associated with hair follicles. • Secretes sebum, a mixture of fats, cholesterol, protein, and inorganic salts. • Keeps hair from drying out and becoming brittle. • Hair • a. Primary function is protection—guards scalp from injury and sunlight, eyebrows and eyelashes protect the eyes, hair in the external ear and nostrils prevent insects and dust from entering.

FUNDAMENTAL PRINCIPLES OF FINGERPRINTING • First Principle: A fingerprint is an individual characteristic, no two fingers have identical ridge characteristics • It is not the shape of a print that is individual, but the number, location and shape of specific ridge characteristics • Specific ridge characteristics are called minutiae

FUNDAMENTAL PRINCIPLES OF FINGERPRINTING • Second Principle: A fingerprint will remain unchanged during an individual’s lifetime • A fingerprint can be obscured by deep tissue damage such as scars or burns • Scars may be useful as points of identification

FUNDAMENTAL PRINCIPLES OF FINGERPRINTING • Third Principle: Fingerprints have general ridge patterns which permit them to be systemically classified. • Classifying the general pattern of fingerprints allows them to be stored in a filing system, which then can be retrieved for comparison. • Modern technology allows this process to be transformed to a computer system- AFIS

History of Fingerprinting • Ancient History- Evidence of ancient Chinese and Babylonian civilizations using fingerprints to sign legal documents. Early Europeans used fingerprints as a seal or mark of authenticity. • 19th century dactylscopy, or the study of fingerprints began. • 1880 Dr. Henry Faulds, and English physician working in Tokyo, published a scientific paper suggesting the use of fingerprints to identify criminals • Mark Twain publishes 2 books (one in 1883 and again in 1894) which fingerprinting is used as evidence to solve a crime

HISTORY OF FINGERPRINTING • 1892, English scientist Sir Francis Galton published a book which noted the importance in calculating the distinctiveness of fingerprint details, and also for sketching out the basics for fingerprint classification system. • 1897 Sir Edward Henry proposed a modified classification system which was adopted by Scotland Yard in 1901, and is still the basis for taking fingerprints in most English speaking countries. This classification system is known as the ten print system. • 1892, Argentina’s police official Juan Vucetich officially indentified a criminal using fingerprints and which sent a mother to jail after killing her 2 sons.

HISTORY OF FINGERPRINTING • 1902, first systematic use of fingerprints in the U.S. by the New York Civil Service Commission for testing • 1904, The use of fingerprints began in Leavenworth Federal Penitentiary in Kansas, and the St. Louis Police Department. They were assisted by a Sergeant from Scotland Yard who had been on duty at the St. Louis World's Fair Exposition guarding the British Display. Sometime after the St. Louis World's Fair, the International Association of Chiefs of Police (IACP) created America's first national fingerprint repository, called the National Bureau of Criminal Identification.

HIRTOSY OF FINGERPRINTING • AFIS was developed by

Classification of Fingerprints and Ridge Patterns • Fingerprints can be classified into three basic patterns, loops, whorls and arches

LOOPS • Most common pattern, with 65% of all fingerprints having loops • Fingerprint pattern with one or more ridges entering from one side, curving, then going out from the same side entered

LOOPS • Loops have two focal points, delta and core • Delta- triangular area found in all loop and whorl patterns • Core- area found near the center of all loop and whorl patterns

LOOPS • There are two subgroups to the loop, the radial loop and the ulnar loop • Radial loop- ridges flow in the direction of the thumb ( radius) • Ulnar loop- ridges flow in the direction of the • little finger (ulna) • European ancestry tend to have more loop patterns on their fingerprints

WHORLS • Second most common pattern, occurring in 30-35% of all fingerprints • Fingerprint pattern with at least two deltas and a core. Whorls take the form of a spiral, shell, circle, target or eye.

WHORLS • There are four types of whorls • Plain • Double whorl- • Central Pocket- • Accidental • Asian and Oriental ancestry tend to have more whorls patterns on their fingerprints.

ARCHES • Arches are the least common and the simplest of fingerprint patterns, occurring in 5% of fingerprints • Fingerprint pattern that has no delta or core. All ridges enter one side and exit the other.

ARCHES • Arches are subdivided into two distinct groups, plain and tented • Plain-Ridges tend to rise in the center of the pattern, forming a wave-like pattern • Tented – contain a sharp spike in the ridges, or the ridges meet at an angle less than 90 degrees. • African American ancestry tend to have more arch patterns on their fingerprints.

Arches

Individualization- Ridge Classifications • To individualize fingerprints you must use the fine structure of ridge characteristics, or minutiae. • There are several classes of minutiae to help individualize fingerprints. • Bifurcation- occurs when a ridge splits or forks into two separate ridges

Individualization- Ridge Classifications • Double bifurcation-occurs when a ridge splits or forks into two separate ridges, and then splits again into two separate ridges • Ridge End - abrupt termination of any ridge. • Lake or enclosure -occurs when a single ridge line bifurcates, then quickly reconnects and continues as a single ridge

Individualization- Ridge Classifications • Island or eye - short ridges that simply start and stop and don’t connect to any other ridge • Dot - a very short island, of basically equal length and width • Bridge -short ridge that runs between two other parallel ridges, sometimes called a “railway tie”

Individualization- Ridge Classifications • Spur- a special bifurcation where one resulting ridge is considerably shorter, ending near the original split/fork

Identifying Fingerprints • Sir Edward Henry developed a ten print system to classify fingerprints and use them for identification. • The first step is to identify the presence of any whorl patterns, the type of whorl, the number of whorls, etc. The whorl pattern is given a number based on which finger it is on. That number will be set up as a fraction • Each response generates a number in the examiner’s code and each numerical response can be translated to a set numerical description.

Identifying Fingerprints • The complete code exactly describes the print in a way people and machines can understand • This presents examiners with a manageable list of possible matches for the fingerprint. • Computer matching of fingerprints is used to make the first big cut of matches, after this manual comparison may still be needed.

Go to Forensic Science book, page 54 • Complete your fingerprinting with graphite & tape. Put it in your notes. • 1. Labe each finger as loop (& type), whorl (& type) or arch (& type) • 2. Complete your primary classification • 3. Find 10 individualized points of reference on each print. Label each

Identifying Fingerprints • There are no legal requirements in the United States on the number of minutiae and their relative location (points) that must match before deciding that a fingerprint belongs to a certain individual. There are 150-200 minutiae in a properly rolled print. Criminal courts will generally accept 8-12 points of similarity as sufficient proof. An newer acceptance level of 10 is typical.

Tru TV fingerprint game • http://www.trutv.com/shows/forensic_files/games/fingerprint/index.html

COMPARE AND CONTRAST LATENT, PLASTIC AND VISIBLE FINGERPRINTS • Latent prints are fingerprints formed by oil and sweat secretions deposited by a person’s finger when they touch a surface or object. Latent prints are invisible and must be developed by chemical or physical means.

Plastic prints are impressions of a fingerprint left in a soft substance such as, wax, soap, putty, gum, stamps, candy bar, or fresh paint. They are also known as indented or molded prints and are not commonly found at a crime scene. COMPARE AND CONTRAST LATENT, PLASTIC AND VISIBLE FINGERPRINTS • Plastic prints are impressions of a fingerprint left in a soft substance such as, wax, soap, putty, gum, stamps, candy bar, or fresh paint. They are also known as indented or molded prints and are not commonly found at a crime scene.

COMPARE AND CONTRAST LATENT, PLASTIC AND VISIBLE FINGERPRINTS • Visible prints are fingerprints that have touched colored materials such as; blood, paint, ink, grease, chalk, mud or dust. Visible prints are not common at a crime scene.

Textbook: Criminalistics pg 405 • Scan through pages 405-418 to find and define some of your vocabulary terms

Textbook: Forensic Science • Discussion: pg 50, first paragraph • Lab activity pg 51 • Pg 53, classify your prints • Statistics of prints, pg 55 • Pg 56, individualization of prints

Unit 4 Fingerprint Identification