Presentation on theme: "11/13/13 AIM: How was fingerprinting developed in forensic science? DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER. HOMEWORK:"— Presentation transcript:
11/13/13 AIM: How was fingerprinting developed in forensic science? DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER. HOMEWORK: Textbook read 72-73 and 76- 77(Anatomy of a fingerprint). What are friction ridges and where are they found?
Dactyloscopy The study of fingerprints Historically William Herschelrequired Indians to put their fingerprints on contracts, and also as a means of identifying prisoners Henry Fauldsclaimed that fingerprints did not change over time and that they could be classified for identification Alphonse Bertillonproposed body measurements as a means of identification; termed anthropometry Francis Galtondeveloped a primary classification scheme based on loops, arches and whorls. Edward Richard Henryin collaboration with Galton instituted a numerical classification system Juan Vucetichdeveloped a fingerprint classification based on Galtons that is used in Spanish-speaking countries
Fingerprinting Recording or Making Prints rolling inked prints primary identification number Lifting Prints Black, white and fluorescent powder Chemicalsninhydrin, iodine, silver nitrate, cyanoacrylate Other Types of Prints Palm, lip, teeth, eye, ear, voice, shoe and footprints
What is a fingerprint? Skin has an outer layer (epidermis) which has ridges projecting inward, and an inner layer (dermis) which has projections pressing into the spaces between ridges A fingerprint is a pattern made by the friction ridges, which is left behind due to sweat and oil that sticks to them. Fingerprints form during the fetal stage of development.
When do they form? In early embryonic development & remain constant
What determines fingerprints? DNA - Genes & environmental forces: pressures within the womb and contact with the amniotic fluid
Formation of fingerprints Skin layer growth – 3-4 month – Middle layer of skin buckles and folds creating the first ridges Creation of ridges – fetus touches surrounding structures, exact position in the womb and the density of the womb's amniotic fluid determine how every individual ridge will form Ridge patterns: 6 months – The ridges on a fetus's fingertips have formed three main patterns categorized as arches, loops and whorls Fingerprint characteristics – two common characteristics found in every fingerprint: ridge end and bifurcation – The sequences of ridge end and bifurcation characteristics are different in every fingerprint
11 Anatomy of Fingerprints Epidermis – Outer layer of the skin Dermis – Inner layer of the skin Dermal papillae – Layer of cells between the epidermis and dermis – Responsible for determining the form and pattern of the ridges on the surface of the skin
Fundamental Principles of Fingerprints A fingerprint is an individual characteristic. A fingerprint will remain unchanged during an individuals lifetime. Fingerprints have general characteristic ridge patterns that permit them to be systematically classified.
Thursday 11/14/13 AIM: How are imprints individual pieces of evidence? DO NOW: Explain how fingerprints are formed HOMEWORK: Textbook read pages 79-80. Answer questions 6-10 on page 100 Wednesday hw: Textbook read 72-73 and 76- 77(Anatomy of a fingerprint). What are friction ridges and where are they found?
DONOW ANSWER DNA controls formation of epidermis and dermis The pressure on the amniotic fluid finalizes the ridge pattern
Fingerprint Ridges Give skin traction for picking up items. The fine lines curve, circle, and arch. Valleys - grooves or furrows Hills - friction ridges
Fingerprint principle 1 A fingerprint is an individual characteristic no two fingers have yet been found to posses identical ridge characteristics
Principle 2 Fingerprints have general ridge patterns that permit them to be systematically classified
Fingerprint Pattern Pores on the ridges Discharge perspiration from the sweat glands Sweat mixed with oil can leave a latent invisible fingerprint
Other Prints Earsshape, length and width Voiceelectronic pulses measured on a spectrograph Footsize of foot and toes; friction ridges on the foot Shoescan be compared and identified by type of shoe, brand, size, year of purchase, and wear pattern. Kendall/Hunt Publishing Company19
Other Prints Palmfriction ridges can be identified and may be used against suspects.
Chapter 4 Other Prints Footprints are taken at birth as a means of identification of infants.
Chapter 4 Other Prints Lipsdisplay several common patterns Short vertical lines Short horizontal lines Crosshatching Branching grooves
Chapter 4 Other Prints Teethbite marks are unique and can be used to identify suspects. These imprints were placed in gum and could be matched to crime scene evidence.
Chapter 4 Other Prints The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.
Chapter 4 Friday 11/15/13 AIM: how are fingerprints identified? DO NOW: List the three major characteristics used to identify fingerprints. Explain why each of your ten fingerprints are different.
Chapter 4 Arch An arch has friction ridges that enter on one side of the finger and cross to the other side while rising upward in the middle. Types Plain- the arch is mild Tented- the arch is spiked upward
Loop A loop must have one or more ridges entering and exiting from the same side it began. Loops must have one delta (aY pattern from diverging ridges) Types Radial-- opens toward the thumb Ulnar-- opens toward the pinky (little finger) Which type of loop is this, if on the right hand? Left hand? deltaΔ
Whorl A Whorl has a minimum of 2 deltas. Types Plain- 2 symmetric deltas and a complete ridge circuit (circular in pattern) Central Pocket- 2 asymmetric deltas, one side appears to be stretched Double Loop- 2 loops and 2 deltas Accidental- a whorl that does not fit the 3 above pattern types 31 Plain whorl
White lines in ridge patterns represent diet pattern. Many white lines indicate celiac disease 36
Determining fetal environment The more symmetrical your fingerprints the more stable the amniotic environment Kendall/Hunt Publishing Company37
Monday 11/18/13 AIM: how are fingerprints analyzed? DO NOW: 1- What are the 3 general fingerprint patterns? 2-Explain the roll of the delta in fingerprint identification HOMEWORK: Using the class information, create a bar graph of the % of fingerprint patterns 2- Do the classroom % match the national average? Kendall/Hunt Publishing Company38
On your computer paper ThumbIndexMiddleRingPinky Right Hand Ridge pattern LeftHand Ridge pattern
Thursday 11/21/13 AIM: how are fingerprints compared? HOMEWORK:Textbook pg 100 questions 3-10. write out the question followed by the answer
Identify each fingerprint pattern. Right Hand Left Hand Right Hand
Fingerprint Identification The uniqueness of a fingerprint can be determined by the pattern of ridges and valleys as well as the minutiae points. Minutiae points are local ridge characteristics that occur at either a ridge bifurcation or a ridge ending. 49
Ridge Characteristics Minutiaecharacteristics of ridge patterns 50 Ridge ending Short ridge Dot or fragment Bifurcation Double bifurcation Trifurcation Bridge Island Enclosure Spur Kendall/Hunt Publishing Company
RIDGE CHARACTERISTICS (Minutiae) COMMON OCCASIONAL RARE Ending Ridge
RIDGE CHARACTERISTICS MAGNIFIED Points 1, 2, 4, 5 are Ending Ridges Points 8, 10, 11 are Bifurcations Point 7 Short Ridge Points 3 and 9 are Dots Point 6 is an Enclosure (ISLAND) Point 6 is an Enclosure (ISLAND) 1 1 2 2 4 4 5 5 8 8 10 11 9 9 7 7 3 3 6 6
How are fingerprints compared? A.Fingerprints are compared by noting the ridge pattern on two prints to determine whether or not they match. B.The minutiae characteristics are then compared C.An identification is established when a number of these characteristics occupy the same relative position on the two prints. A.Fingerprints are compared by noting the ridge pattern on two prints to determine whether or not they match. B.The minutiae characteristics are then compared C.An identification is established when a number of these characteristics occupy the same relative position on the two prints.
Comparison There are no legal requirements in the United States on the number of points. Generally, criminal courts will accept 8 to 12 points of similarity.
Primary Classification Kendall/Hunt Publishing Company62 The HenryFBI Classification Each finger is given a point value rightleft
Primary Classification Assign the number of points for each finger that has a whorl and substitute into the equation: Kendall/Hunt Publishing Company63 right right left left left index ring thumb middle little + 1 right right right left left thumb middle little index ring +1 That number is your primary classification number =
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. 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. Spike or tent
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. 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 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. 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. Plain Whorl Central Pocket Whorl
Whorls – Part 2 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. Double Loop Whorl Double loop whorls are made up of any two loops combined into one print. Delta
WHAT IS A FINGERPRINT? A fingerprint is a pattern comprised of ridges and valleys. A Ridge – is a high. A Valley – is a depression or low. A fingerprint is a pattern comprised of ridges and valleys. A Ridge – is a high. A Valley – is a depression or low. Friction ridges are also found on our palms, feet and toes.
Anatomy of fingerprints Finger touches a surface – Perspiration – Oils from hairy portions of the body – Transferred onto surface Leaves fingerprint 70
71 What is a Fingerprint? Skin has an outer layer (epidermis) which has ridges projecting inward, and an inner layer (dermis) which has projections pressing into the spaces between ridges A fingerprint is a pattern made by the friction ridges, which is left behind due to sweat and oil that sticks to them. Fingerprints form during the fetal stage of development.
There are 3 types of fingerprints 1. Visible – left by dirt, grease, blood, etc. Does not need processing
There are 3 types of fingerprints 2. Impression – indentation in soft material (butter, putty, tar, etc.) Does not need processing
There are 3 types of fingerprints 3. Latent – requires processing to make visible and suitable for analysis
What are the invisible components? Multiple sweat glands secrete onto fingers, palms, etc. Sweat contains: Inorganic ions (Na +, Cl - ) Proteins, amino acids Lipids Other
76 Lifting Latent Prints Developing a print requires chemicals that react with secretions that cause the print to stand out against its background. It may be necessary to attempt more than one technique, done in a particular order so as not to destroy the print. Powders--adhere to both water and fatty deposits. Choose a color to contrast the background. Iodine--fumes react with oils and fats to produce a temporary yellow brown reaction.
Physical Development: Dusting Apply powder to latent print or area. Powder adheres to print. Brush and Powder
Physical Development: Dusting Apply powder to latent print or area. Powder adheres to print. Magnetic Brush and Powder
79 Lifting Latent Prints (cont) Ninhydrin--reacts with amino acids to produce a purple reaction. Silver nitrate--react with chlorides to form silver chloride, a material which turns gray when exposed to light. Cyanoacrylate--super glue fumes react with water and other fingerprint constituents to form a hard, whitish deposit. In modern labs and criminal investigations, lasers and alternative light sources are used to view latent fingerprints. It was first used by the FBI in 1978. Since lasers can damage the retina of the eye, special precautions must be taken and a filter used.
Chemical Development: 1. Silver Nitrate No longer used (messy, not sensitive) Silver reacts with Cl - ions in print
Chemical Development: 2. Iodine Fuming Iodine sublimes (solid gas) Iodine reacts with lipid components; becomes trapped in the print. Fuming wand or chamber Dirty Brown Color Fingerprints > Analysis