fingerprints...history of fingerprinting •henry fauld was a doctor in japan who wrote an article...
TRANSCRIPT
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Fingerprints
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History of Fingerprinting
• People have always wanted a full proof way to identify someone.
• The first system was created by Alphonse Bertillon (1883)
• Used a detailed description plus full length and profile photographs.
• Also used precise body measurements
• This included height, reach, width of head & length of left foot.
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History of Fingerprinting
• Police used Bertillon's method for 20 years
Early use of fingerprints
• Chinese used fingerprints to sign legal documents 3000 years ago
• It was only used in a few places, so no system for identification was created.
• Around 1880 William Herschel started using handprints for I.D. on contracts in India.
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History of Fingerprinting
• Henry Fauld was a doctor in Japan who wrote an article on how fingerprints could be use for identification.
• He thought that ridge patterns in the skin could be used to identify criminals.
• Wanted to pay for a fingerprint bureau at Scotland Yard.
• He was turned down.
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History of fingerprinting
• 1892 – Francis Galton published the textbook “fingerprints”
• It suggested methods for recording them
• Found three types of fingerprint patterns
• Loops, whorls and arches
• Showed that no two people had the same fingerprints.
• Also showed they did not change with time.
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History of Fingerprinting
Two classification systems for fingerprinting were created.
1) Dr. Juan Vucetich – argentine police officer
- His system is still used in most Spanish speaking countries
2) Sir Edmund Richard Henry
- His system is used in most English speaking countries.
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Adoption of Fingerprinting
• Bertillon’s body measurement system had problems.
• The measurements were not always accurate
• 1903 – convict Will West is sent to Fort Leavenworth Prison.
• There was already a Will West in the prison.
• The two men looked identical and had identical measurements.
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Adoption of Fingerprinting
• You could only tell them apart by fingerprints
The first official use of fingerprinting was in New York city in 1901.
• Was used to certify civil service applicants
• Police, firemen, postmen, etc.
1924 – FBI and Leavenworth prison records put together to make a fingerprint database
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Adoption of Fingerprinting
• FBI has the largest collection of fingerprints in the world.
By WWI (1912), all of Europe was using fingerprinting for identification.
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Fundamental Principles of Fingerprints
There are three basic principles
1) No two fingerprints have yet been found to possess identical ridge characteristics.
• About 64 billion different possibilities for a fingerprint.
• Odd extremely small two people would have identical prints.
• In 110 years, no two have been identical
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Fundamental Principles of Fingerprints
• It is based on ridge characteristics
• = ridge endings, bifurcations, enclosures and other ridge details which must match in two fingerprints to establish a common origin.
• Not only do the parts of he ridges have to match, they must be in the exact same location on the finger.
• In court, a point by point comparison is made, using charts, numbers and descriptions.
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Fundamental Principles of Fingerprints
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Fundamental Principles of Fingerprints
• Full prints are easy to identify
• Up to 150 individual ridge characteristics
• Most crime scene prints are partial prints or smudges.
• Experts disagree as to how many ridge characteristics are needed to identify someone.
• Ranges from 8 - 16
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Fundamental Principles of Fingerprints
• Fingerprint identification is entirely dependent on the experience and knowledge of experts.
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Fundamental Principles of Fingerprints
2) A fingerprint remains unchanged during an individual’s lifetime.
• Fingers and thumbs, palms and soles of feet have friction ridges for better grip.
• The shape of these skin ridges are what we see when we look at fingerprints.
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Fundamental Principles of Fingerprints
Skin
• Made of several layers of cells
1) Epidermis – outermost layer
2) Dermis – inner layer
3) Dermal papillae – layer between dermis and epidermis
- This layer makes the fingerprints.
- This layer develops in the fetus and never changes
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Fundamental Principles of Fingerprints
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Fundamental Principles of Fingerprints
• Each skin ridge has a single row of sweat gland pores.
• This sweat and oil is what is left behind as a fingerprint.
• Latent fingerprint = an invisible fingerprint made by deposits of oil and/or sweat.
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• Criminals try to change their fingerprints
• If you go down far enough, it will leave a scar in the dermal papillae
• This gives us another way to identify the person
• John Dillinger was a famous mob boss.
• He dipped his fingers in acid to get rid of his fingerprints.
• When he died, he was identified by his fingerprints.
Fundamental Principles
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Fundamental Principles 3) Fingerprints have general ridge patterns that permit them to be systematically classified.
• There are three general patterns of fingerprints
• Loops, whorls and arches
• 60 – 65% of people have loops
• 30 – 35% of people have whorls
• About 5% of people have arches
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Fundamental Principles Loops – have ridge lines that enter from one side of the pattern and curve around to exit from the same side of the pattern.
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Fundamental Principles • If the loop opens toward the little finger, it is
called an ulnar loop.
• If it opens toward the thumb, it is a radial loop.
• A type line is ridges that peal away from the loop.
• A delta is when the type line and loop form a tent shape.
• The core is the center of the loop.
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Fundamental Principles Whorl – ridge patterns that are generally rounded or circular and have two deltas.
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Fundamental Principles
Four types of Whorls
1) Plain whorls have at least one ridge that makes a complete circle.
• If you draw a line between the two deltas and they touch a ridge.
2) Central pocket whorl – has at least one ridge that makes a complete circle.
• If the line between the deltas does not touch a ridge line.
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Fundamental Principles
3) Double Loop – two loops in a fingerprint
4) Accidental – a combination of forms except for the plain arch.
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Fundamental Principles Arches – don’t have type lines, deltas or cores
• Least common type of fingerprint
1) Plain arch – starts on one side of the finger, makes an arch, goes out the other side.
2) Tented arch – same as a plain arch, but comes to a point at the top.
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Fundamental Principles
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AFIS • AFIS = Automated Fingerprint Identification
System
• The Henry system was not easy to use or to store information.
• Until computers, it was the best we had.
• 1970 – AFIS created – computerized identification of fingerprints.
• 1999 – IAFIS – Integrated AFIS
- This links all 50 states’ AFIS databases with the FBI’s.
- Nearly 50 million fingerprints in the system
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AFIS • How AFIS works
• We scan and digitally encode fingerprints
• It puts markers on loops, whorls, arches, ridge endings and bifurcations.
• Bifurcation = branching of one ridge into two ridges
• It shows exactly where on the finger each marker is.
• Can check 500,000 ten finger prints in less than a second.
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AFIS
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AFIS • It has a scrolling system and will kick out a list
of prints that most closely match the sample
• An expert in fingerprints will make the final decision.
• In No Suspect cases in San Francisco, it identified 1001 people out of 5514 cases (18%
• If done manually, it averaged 8%
• Systems will automatically filter out imperfections.
• It will enhance the image and create a computer image of the print.
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AFIS • The computer print and the suspect’s print are
compared side by side by an expert.
• We no longer use Ink for fingerprints in most places.
• We now use LiveScan
• This digitally scan fingers and palms and puts them into AFIS.
• It only takes minutes to see if they match any other crimes.
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AFIS • Problems with AFIS
• Latent prints may not get a hit because the file print is poor.
• Have to do manual comparisons if this happens
• AFIS systems are made by several companies
• All of them do the same thing, but don’t do it in the same way.
• Have different measuring systems & different features
• They can send information to the FBI, but maybe not to other states.
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Detecting Fingerprints • Visible prints are not a problem.
• Latent (invisible) prints require several different techniques to be seen.
• On Hard surfaces (glass, tile, painted wood), we use powders or super glue fuming.
• On Soft surfaces (paper, cloth, cardboard), we use different chemicals.
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Ways of Detecting Fingerprints • RUVIS = Reflected UltraViolet Imaging Systems
• Lets us see fingerprints on hard surfaces with powders.
• Shoots UV light which reflects and shows prints
• They can lift or photograph the print once it has been found.
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Finger Print Dusting
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Developing Latent Prints • 1) Fingerprint powders
• Fine powder that sticks to sweat and oils on fingerprints
• Use a camel hair or fiberglass brush to give a light dusting over fingerprint
• Usually use grey and black powders
• Use grey for dark surfaces, mirrors and glass
• Use black for light surfaces.
• We have magnetic powders in black and grey
• Used on finished leather and rough plastics
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Developing Fingerprints
• Fluorescent powders can light up a print so you can photograph it.
2) Iodine Fuming
• Iodine does Sublimation = turning from a solid to a gas with no liquid stage.
• Put into chamber with evidence, heat crystals and fume the object.
• This makes the print visible
• We photograph the prints.
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Developing Fingerprints
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Developing Fingerprints
3) Ninhydrin
• This mixes with perspiration in prints
• Turn the print bluish purple
• Used on porous surfaces
• Sprayed with an aerosol can
• Takes and hour or two for prints to appear.
4) Physical developer
• Used when the other do not work
• Used on wet, porous materials
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Developing Fingerprints
• It destroys all of the proteins, so it has to be used last.
5) Super glue fuming
• Can be used on porous and non-porous surfaces
• Put super glue on cotton ball mixed with sodium hydroxide
• Put in a closed cabinet with the evidence and heat.
• Fumes stick to prints in 4-6 hours.
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Super Glue Fuming Alternate Light Source
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Developing Fingerprints
• Can also be used in closed cars.
• Now we have a hand held version to use on a site.
6) Alternate Light Source
• Areas have to have chemicals used on it before this can be used
• Which chemical used depends on what the material is.
• Need to be an expert to know which one to use
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Developing Fingerprints
• New chemicals for this are being created
- None of the chemicals used to find fingerprints mess with the DNA.
- Regardless of which method you use, the results need to be determined by a fingerprint analysis expert.
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Preserving Developed Prints
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Preserving Developed Prints
• You need a permanent copy for future use
• Must take a photograph at the scene before you make any attempt at preserving the print.
• Photo must include where it is in respect to the other evidence.
• If it is a small object (can, bottle), you can take the whole thing with you.
• The print should be covered with cellophane to preserve it.
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Preserving Developed Prints
• On large objects, the print has to be “lifted”
1) Dust print
2) Use a wide piece of clear tape
3) Use the tape to pull up the dust with the print
4) Place on a background that will show up the print.
• Most police use a ready made version of this.
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Preserving Developed Prints
• The tape and cardboard at attached together with a piece of celluloid between them
• Remove the celluloid, peel tape, stick to powder, press back onto the cardboard.
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Digital Imaging for Fingerprint Enhancement
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Digital Imaging for Fingerprint Enhancement
• Digital imaging = a process through which a picture is converted into a series of square, electronic dots known as pixels.
• Put pixels together to make a digital image.
Black and white images are called grayscale images.
• Black is 0 and white is 255.
• Pixels can be anywhere between 0 and 255
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Digital Imaging for Fingerprint Enhancement
• The intensity of the pixels can be manipulated by a computer.
• Once the picture is in digital form we can try several different ways to enhance the image.
• Colored surfaces make it harder to get a sharp image.
• Have to digitally remove the colored back ground to get a sharp image.
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Digital Imaging for Fingerprint Enhancement
• If the print is colored (iodine, Ninhydrin),
• You isolate the print color to make it stand out
• With scaling and resizing tools, we can enlarge a part of the print for a closer look.
• The compare function lets you put two images side by side.
• You can zoom into both images to compare points.