Unit 2 Review-Fingerprints. 1. Match the definitions of the word on the right with the vocabulary terms on the right.

Transcription

1 Name: KEY Unit 2 Review-Fingerprints 1. Match the definitions of the word on the right with the vocabulary terms on the right. 1. Fluoresce O 2. Iodine fuming F 3. Latent fingerprint P 4. Livescan A 5. Ninhydrin D 6. Plastic print Q 7. Minutiae (ridge characteristics) J 8. Ridges H 9. Grooves L 10. Visible prints B 11. Whorl N 12. Ulnar loop R 13. Radial loop C 14. Arches I 15. Fingerprint S 16. AFIS G 17. Loop M 18. Type lines T 19. Core E 20. Delta K A. An inkless device that captures a digital image of fingerprints and palm prints and electronically transmits them to an AFIS. B. A fingerprint made when the finger deposits a visible material such as ink, dirt or blood onto a surface. C. A loop that opens toward the thumb. D. A chemical reagent used to develop latent fingerprints on porous materials by reacting with amino acids in perspiration. E. The approximate center of a fingerprint pattern. F. A technique for visualizing latent fingerprints by exposing them to iodine vapors. G. Systems which are designed to place fingerprints into computers so as to allow the computer to categorize, compare, and match fingerprints. H. The elevated, curved lines of a fingerprint pattern. I. Fingerprint patterns which do not have type lines, deltas, or cores. J. Ridge endings, bifurcations, enclosures, and other ridge details which must match in two fingerprints to establish their common origin. K. A ridge point nearest a type line divergence. L. The dips between the raised curved lines of a fingerprint pattern. M. Fingerprint patterns which the ridge lines enter from one side of the pattern and curve around to exit the same side of the pattern. N. Fingerprint patterns which must have type lines and a minimum of two deltas. O. To emit visible light when exposed to light of a shorter wavelength. P. Fingerprints which are invisible to the naked eye. Q. Ridge impressions left on a soft material such as putty, wax, soap, or dust. R. A loop that opens toward the little finger. S. A reproduction of friction skin ridges found on the palm side of the fingers and thumb. T. The pattern area of a fingerprint surrounded by two diverging ridges.

2 2. State the three fundamental principles of fingerprints st : A fingerprint is an individual characteristic; no two prints have ever found to be the same nd : A fingerprint remains unchanged during an individual s lifetime rd : Fingerprints have general ridge patterns that permit them to be systematically classified. 6. How did the following people contribute to the modern use of fingerprinting? a. Alphonse Bertillon Created the system of body identification based on eleven measurements and detailed photographs. His system was widely accepted as a means of identification before the wide spread use of fingerprinting. b. The Chinese The Chinese used fingerprints to sign legal documents as far back as three thousand years ago but it is still up for debate on whether the use of fingerprints was ceremonial or if they were used as personal identification. c. William Herschel William Herschel was stationed in India and required people to sign contracts with the imprint of their right hand that had been pressed against an ink pad. The use of the hand print was debated as either a Hindu custom of leaving a trace of themselves behind or as personal identification. It is unclear what the original intent was but he made his practice known after Henry Fauld published his work on fingerprints for identification purposes. d. Henry Fauld Henry Fauld was the first person to suggest that fingerprints could be used to identify criminals. He proved this through a case where he compared a fingerprint on a whitewashed wall to a suspect to prove the identity of the thief. e. Francis Galton Francis Galton wrote the textbook Finger Prints which classified prints into the three main categories we use today. He also demonstrated that no two fingerprints are alike. f. Dr. Juan Vucetich Dr. Juan Vucetich was the first person to come up with a useable classification system that allowed thousands of prints to be filed and recalled when needed. g. Sir Edward Richard Henry Sir Edward Richard Henry also created a useable classification system that allowed thousands of prints to be filed and recalled when needed. Most English speaking countries use some form of his system. h. Will West Will West is actually two people with the same name that had almost identical measurements and looks under Alphonse Bertillon s measurement system. Because of this, the measurements, etc. could not be used as a means of personal identification and it started the hunt for a more unique way of personal identification the fingerprint.

3 7. Explain the anatomy of a fingerprint. The papillae grow faster than the layers of skin around it which creates friction and causes the skin to push up in places. These areas are called ridges and it is these ridges that make up your fingerprint. The skin produces sweat that exits as the surface through pores. This sweat combined with oils secreted in the hairy parts of the body are what leaves a distinct pattern when you touch an object. 8. Explain why no two prints are ever the same-even if the DNA is identical. The fingerprint pattern is made through a combination of DNA and the physical environment in the womb. Because no two people ever have the exact same experience and contacts in the womb in the exact same way, the fingerprints will be different for each person, regardless of the DNA. 9. Fill in the following chart about the methods to develop latent prints. Method Type of Surface Used On How it Works (What does it adhere to?) Powders Nonabsorbent smooth surfaces like glass or door handles The powder is lightly dusted onto the surface where prints are suspected of being. The powder adheres to sweat and oil residue, leaving a visible print that can be lifted with tape and analyzed. Iodine Fuming Porous surfaces like paper or fabric The object is placed in an enclosed cabinet with iodine crystals. The iodine crystals are heated up and become a vapor. This vapor reacts with the print and allows the print to be seen. The print fades as soon as the process is stopped so you have to take a picture immediately or fix the print with a corn starch solution. Ninhydrin Physical Developer Super Glue Fuming Porous surfaces like paper or fabric Porous articles that could have been wet at one time. Nonporous surfaces like metals, tape, leather, plastic. It is a chemical that is sprayed onto the object. Ninhydrin will react with the trace amounts of amino acids in sweat and will turn the print a purple-blue color. Prints become visible within an hour but can take up to 24 hours. The process can be sped up using heat. A silver nitrate based liquid is heated up and applied after iodine or ninhydrin fuming. The mixture reacts with the previous chemicals to create a visible print. The super glue is heated up causing vapors to fill an enclosed case. These vapors adhere to the latent print to create a white appearing latent print. Now, a small hand held wand can do the same thing and can be used at a crime scene. 10. Explain how AFIS works to identify a print.

4 AFIS is a computer system that maps the fingerprint pattern, bifurcations, ridge endings, deltas, cores and their relative location to each other. These mapped fingerprints are stored in a database and can be used to create a possible list of matches. 11. What are some common misconceptions about AFIS? Some common misconceptions are that the AFIS system makes the match for you but in reality, a human must make the final match. AFIS only provides you with a list of possible matches. Another common misconception is that there is only one AFIS but in reality, most municipalities have their own system for local prints, as well as the national database with the FBI. 12. Label the following diagram of the skin. Ridge Pores Epidermis Papillae Dermis Sweat Gland Duct Word Bank: Sweat Gland Pores Sweat Gland Duct Papillae Ridge Epidermis Dermis Nerves Sweat Gland Nerves

5 13. Identify each of the following fingerprints as one of the following: A. Loop D. Plain Arch B. Plain Whorl E. Tented Arch C. Whorl Double Loop F. Central Pocket Loop D C E F A B C A A 14. Determine if the following two prints are from the same person. Explain your reasoning. These two fingerprints are not from the same person. Although the general pattern is the same (central pocket loop, the deltas, cores, bifurcations, and ridge endings are all in different locations relative to each other. There are also some ridges that are different between the two prints.

6 Foot Printing 15. How often are footprints found at a crime scene? Footprints are found about 40% of the time. 16. What are the two types of footprints and explain how they are different. The two types of footprints are positive and negative prints. A positive print is left when a person transfers matter from their shoe to a surface leaving a print. A negative print is left when a person removes residue from the surface it walks on leaving a 3-D impression on the shoe. 17. What are class characteristics and what are they used for? Give an example. Class characteristics are things that are similar for all shoes made by that manufacturer regardless of location or size. An example of a class characteristic would be the four round spring patterns on the heel of all Nike Shock shoes. These characteristics help investigators determine the manufacturer of the shoe. 18. What are individual characteristics? Give an example. Individual characteristics are the characteristics that are unique to an individual shoe. For example, the surfaces a person walks on could puncture or scar the sole, remove pieces of foam, or in some other way alter the sole of the shoe that is unique to that shoe. 19. What is wear pattern? A wear pattern is how the sole of the shoe starts to wear out. The pattern is caused by how the person walks in the shoe. 20. Label the following wear patterns as supination, pronation, or neutral. Pronate Neutral Supination 21. What are some differences between male and female footprint patterns? Smaller footprints that point slightly outwards with a small stride, tend to point towards a female making the print. Prints that are larger, toes that point straight out or are tilted slightly outwards with a larger stride, tend to point towards a male making the print. 22. What other information can you tell from footprints? You can tell the rate that the person was moving by looking at the stride length, as well as where the deepest part of the impression is. You can also get an estimation of weight, and if the person was carrying an object on one side. You can also use a person s gait in combination with the length of the print to estimate the height of a person.