Fingerprints

1. Fingerprints Pleasant Valley High School Forensic Science ACOS 2.2, 2.3

2. Fingerprinting Lab • Follow my verbal directions for this lab. You will have two days to complete this lab. ACOS 2.2, 2.3

3. Catalyst • Examine your thumbs on both hands. Record any observations you have about both thumbprints. ACOS 2.2, 2.3

4. Quick Experiment • You have now seen your thumbprints as a positive imprint. • What you are seeing is known to members of the Forensics community as Friction Ridges. These lines are composed of valleys (Grooves) and hills (Friction Ridges). When you see an inked print, you are seeing the pattern of the friction ridges. ACOS 2.2, 2.3

5. Timeline of Fingerprinting 1888 – Galton and Henry develop classification systems 1891 – Ivan Vucetich made important changes to the collection process (10 digits, use cards) 1896 – Henry creates the ten card and divided FP’s into modern groups • B.C. China – documents showing negative images of FP’s • 1792 – 1750 B.C. – Ancient Babylon used prints to identify sculptors of clay pottery • 1684 – Dr. Nehemiah writes a paper describing patterns of FP’s • 1788, Johann Mayer notes individuality of FP’s • 1823 – Jan Purkyn describes 9 print patterns • 1856 – Sir William Hershel noted that fingerprints do not change with age ACOS 2.2, 2.3

6. Early Techniques • Alphonse Bertillon- system of precise body measurements (anthropometry) • Bertillon’s system rested on that body measurements never change after the age of 20 • Skeleton sizes were thought to be so diverse that no two people could have the same measurements • System included 11 measurements: outstretched arms, head length and width, left foot length, left little finger length, trunk height, body height, width and length of right ear, length of the left forearm, sitting height • He also documented hair color, eye color, and skin tone ACOS 2.2, 2.3

7. Anthropometry • For twenty years, anthrompometry was thought to be the most accurate measurement system • Once police looked for a more efficient way to identify people, the fingerprinting system came through • Today, fingerprinting is the pillar of criminal identification ACOS 2.2, 2.3

8. Early use of Fingerprints • Documentation of Chinese using FP’s to sign legal documents as far back as 3,000 years ago • Several years before Bertillon began work, FP’s were used in India to “bind” someone to a contract • Scottish physician, Henry Fauld, published papers on the potential application of FP’s to personal identification ACOS 2.2, 2.3

9. Francis Galton • 1892- published book Finger Prints • He discussed the anatomy of fingerprints and suggested techniques for recording them • Galton also assigned fingerprint types: loops, whorls, and arches • His book demonstrated that no two prints are exactly alike • Prints remain unchanged year after year ACOS 2.2, 2.3

10. Basis for Fingerprinting • A Fingerprint is not shared by any two people • A Fingerprint remains unchanged throughout life • Fingerprints exhibit general patterns that provide a basis for classification. ACOS 2.2, 2.3

11. United States v. Byron C. Mitchell • Pennsylvania-1999 • Admissibility of fingerprint evidence was challenged • The defense stated that the fingerprints could not be proven to be unique under the current research • After 4 days of hearings, the judge upheld the research on fingerprints and ruled that: • Human friction ridges are unique and permanent • Human friction ridge skin arrangements are unique and permanent ACOS 2.2, 2.3

12. No 2 Identical Prints • Galton calculated that there are 64 billion documented that can help to support this • Galton’s calculations were challenged and no matter what formula is used there is the same result: • The probability for the existence of two identical fingerprint patterns in the world’s population is extremely small • In 90 years of research, no two prints have ever been identical ACOS 2.2, 2.3

13. Minutiae Points • AKA: Ridge Characteristics • The identity, number, and relative location of characteristics that impart individuality of a fingerprint • An easier definition: the ridges and valleys of a fingerprint • There are as many as 150 minutiae points and ridges on the average print ACOS 2.2, 2.3

14. Some Reality of prints • CSI Lies to You!!! • Former CSI from the Gadsden Police Department, Deanna Rice: • “I have never lifted a complete print at a crime scene. Tell me what criminal is stupid enough to gingerly press their fingers on a smooth surface just so I can get their fingerprints” ACOS 2.2, 2.3

15. Breakdown of Prints • Patent Prints • When a substance such as blood, ink, paint, dirt, or grease on the perpetrators hands leave a visible print behind • Latent Prints • Invisible and require dusting or other processing/lighting to reveal • Plastic Prints • Occur when perpretrator touches a soft substance such as wax, putty, butter, or even dust. Seen as a 3D image ACOS 2.2, 2.3

16. Latent Prints • Your skin has openings called pores that are the location of perspiration of sweat and body oils • When you make contact with a surface your body oils stick to a surface in the shape of your fingerprints • Prints left with this technique at a crime scene are called latent prints ACOS 2.2, 2.3

17. Print Types • Three categories: Loops, Whorls, and Arches • 65% of population has loops • 30% has whorls • 5% has arches ACOS 2.2, 2.3

18. Loops • A class of fingerprints characterized by ridge lines that enter from one side of the pattern and curve around to exit from the same side of the pattern ACOS 2.2, 2.3

19. Two major Loop Types • Ulnar Loop- loop opens toward the little finger • Radial Loop- loop opens toward the thumb ACOS 2.2, 2.3

20. Whorls • A class of fingerprints that include ridge patterns that are generally rounded or circular in shape and have two deltas ACOS 2.2, 2.3

21. Four distinct loop types • Plain- one ridge makes a complete circle • Central pocket loop- if two deltas do not touch on the circle • Double loop- two loops combined in one fingerprint • Accidental- the catch all category, if the print does not fall into any other category ACOS 2.2, 2.3

22. Accidental Whorl Double Loop Whorl Central Whorl Plain Whorl ACOS 2.2, 2.3

23. Arches • A class of fingerprint that is characterized by ridge lines that enter the print from one side and flow out the other side ACOS 2.2, 2.3

24. Plain arch- simplest of all prints, line enters on one side of print and exits the other side • Tented arch- sharp spike in the center of the print ACOS 2.2, 2.3

25. Unchanging Prints • Similar friction ridges and minutiae can be found on the palms of the hand and on the feet • These skin characteristics were designed by nature to enhance our grip and resist slippage • These ridges and minutiae do not change throughout life ACOS 2.2, 2.3

26. Frankensteining • Can you change your fingerprints to prevent being caught? • The answer is NO!! • Your fingerprints are created during womb development • You can not ever change your fingerprints • You can damage or mutilate them, but that just makes you more unique ACOS 2.2, 2.3

27. Mini Case Study • John Dillinger, also known as Public Enemy Number One went through much travesty to evade police • He had facial reconstructive surgery and acid washed his prints in an effort to avoid arrest. • When he was finally shot and taken to the morgue, prints taken at the morgue matched those on file already. ACOS 2.2, 2.3

28. Skin Layers • Outer layer of skin: Epidermis • Inner layer of skin: Dermis • Layer separating the 2 layers: papillae ACOS 2.2, 2.3

29. Formation of FP’s • An animal’s external body tissue (skin) is made up of an inner dermis and an outer dermis • FP are created in a special layer between the two derma where new skin is produced (the basal layer) • FP begin forming in the 10th week of pregnancy • Because the basal layer grows faster than the two derma, it collapses and forms intricate shapes ACOS 2.2, 2.3

30. Dermal Papillae • Your fingerprints are determined by the papillae layer • In order to alter your prints you must damage through the first layer of skin…ouch!!! • Why not just wear gloves? ACOS 2.2, 2.3

31. Anatomy of a FP ACOS 2.2, 2.3

33. Print Classification • Henry System- adopted in 1901, looked at ridge patterns on all 10 fingers, but only accommodated 100,000 sets of prints • Primary Classification- divides all fingerprints in the world into 1024 categories • Turns patterns into fractions • 1/1 means that all of the fingers have the same patterns • Approximately 25% of the population have 1/1 ratio ACOS 2.2, 2.3

34. Uses of these systems • 10 finger system is only of use when the investigator has the names of the suspects on hand • Can be entered into a database and matched ACOS 2.2, 2.3

35. AFIS • Computer database of all fingerprints in the country • Monitored by the FBI • Allows for electronic comparison of a latent print to a known print • Helps to identify suspects ACOS 2.2, 2.3

36. AFIS • The computer’s search determines the degree of correlation between the location and the relationship of minutiae of both the search and file prints • Prior to AFIS, police had to compare prints by hand to known suspects from previous cases or that had been printed already ACOS 2.2, 2.3

37. Latent Details • Visible Prints- made by touching fingers to a surface after the ridges have been in contact with colored material such as blood, ink, or paint • Plastic Prints- left on soft material such as putty, wax, soap or dust • Latent Prints- transfer of by oils and can not be seen by the naked eye ACOS 2.2, 2.3

38. Dusting for Prints • Powders are brushed onto a non-absorbent surface and will adhere to the oils left by the hand • Gray or Black powders are used to lift most all prints • Specialized clear tape known as lifting tape is used to store the print safely ACOS 2.2, 2.3

39. Fuming for Prints • Exposing a piece of evidence to fumes of super glue will expose prints • Either combine cotton cloth, sodium hydroxide and super glue • OR • Heat the super glue to allow evaporation ACOS 2.2, 2.3

40. Preserve the Print • Photograph the print • Cover with cellophane tape • Place on latent print recovery card • Card should be a contrasting color to the color of the powder used ACOS 2.2, 2.3

41. Digital Imaging • Computers can enhance and darken the print to make an easier image to read ACOS 2.2, 2.3

42. ACOS 2.2, 2.3