What are Fingerprints? If a finger touches a surface, perspiration and oils from the body are transferred onto the surface, leaving an impression of the finger’s friction ridge patterns. Fingerprints may contain traces of any material found in perspiration including DNA and chemicals such as nicotine.

What are Fingerprints? Friction ridges are found on skin in the following regions: Palms of hands Palmar aspect (palm-side) of fingers Soles of feet Solar aspect (sole-side) of toes They exist to give firmer grip and resistance to slippage. The number of ridges and their shape is largely determined by genes.

Skin Surface Outer surface layer of skin is the epidermis. The inner layer of skin is the dermis. Between these two are the dermal papillae. The papillary pattern determines the form and pattern of the friction ridges on skin surface.

Skin Surface Each skin ridge is populated by a single row of pores that are openings for ducts leading from the sweat glands. Perspiration is released and deposited on the surface of the skin through these pores.

Fingerprints are Unique Dermatoglyphics is the study of fingerprints. No two fingers have yet been found to have identical ridge characteristics (minutiae). Ridge pattern remains unchanged throughout life.

Fingerprints do not Change Friction ridge pattern of skin develops in utero (before birth) due to uneven stresses in the different layers of the developing skin. Identical (monozygous) twins have the same DNA. have different fingerprints.

Intentionally Altering Fingerprints Very difficult to do, but there has never been a lack of trying. Bank robber John Dillinger attempted to burn off his fingerprints with corrosive acid. They grew back. Illegal immigrants and criminals sometimes undergo finger print plastic surgery. They can still be identified by palm prints and DNA. To change the pattern requires obliteration of the dermal papillae (1- 2 mm deep). Attempts to destroy the pattern can backfire and cause more unique details!

Types of Fingerprint Patterns There are 3 basic fingerprint patterns loops (60-65% of population) whorls (30-35%) arches (5%)

Loops Have ridges entering from one side of the print, turning, and leaving from the same side. The pattern area of the loop is surrounded by two diverging ridges known as type lines. The approximate center is called the core. The ridge point nearest the type line divergence is known as the delta (capital greek letter Δ).

Loops 65% of the population have loops. All loops must have one delta. If the loop opens toward the little finger then it is a ulnar loop. If the loop opens towards the thumb then it is a radial loop.

Special Loops The double loop is made up of two loops combined into one fingerprint. The pocked loop has a small circle at the core.

Arches In an arch, ridges enter from one side of the print and exit on the opposite side.

Arches Arches are divided into two distinct groups: plain arches tetrarches or tented arches The tetrarch consists of an upthrusted ridge in the center of the arch.

Whorls All whorl patterns must have a core and at least two deltas

Other Patterns An accidental pattern contains two or more patterns, but not the plain arch, and is not covered by other categories. It may consist of a combination loop and plain whorl or loop and tented arch.

Types of Prints Latent: hidden or invisible Made by natural body secretions of the hands and fingers (perspiration & grease) Requires dusting or other method to make visible Patent: visible to the naked eye Blood, ink, dirt, glass Plastic: a 3-D fingerprint Wet paint; Soft material like clay

Impressions and Prints Impression - 3-D in soft surface; often visible Print - 2-D transfer of skin perspiration, oils, etc; usually latent

Fingerprint Points The individuality of a fingerprint is determined by a careful study of its ridge characteristics (minutiae points). Specific traits found in friction ridges are used to establish an identification The average finger has between 75 and 175 points of identification.

Types of Points

Matching Points For two points to match they must be at the same location on the fingerprint be the same type. 16 matching characteristics have been suggested to establish the uniqueness of a print.

Powder Techniques Used on non-absorbent surfaces Tipped or very softly brushed on Various Types Black powder (carbon) Grey powder (Aluminum dust) Fluorescent Powder (seen in UV light)

Chemical Techniques Iodine Fuming - for latent prints Ninhydrin - latent prints on paper & porous surfaces Silver Nitrate - for porous surfaces Super Glue Fuming - Non-porous surfaces

Story Time - Juan Vucetich and the origins of forensic fingerprinting In 1892, two boys were brutally murdered in the village of Necochea, in Argentina.

Story Time - Juan Vucetich and the origins of forensic fingerprinting Suspicion fell on a man named Velasquez, a suitor of the children's mother, Francisca Rojas. But even after torture, the police could not get him to confess.

Story Time - Juan Vucetich and the origins of forensic fingerprinting But even after torture, the police could not get him to confess.

Story Time - Juan Vucetich and the origins of forensic fingerprinting Investigators found a bloody fingerprint at the crime scene and contacted Juan Vucetich, who was developing a system of fingerprint identification for police use. 

Story Time - Juan Vucetich and the origins of forensic fingerprinting Vucetich compared the bloody fingerprint with those of Velasquez.

Story Time - Juan Vucetich and the origins of forensic fingerprinting They did not match.

Story Time - Juan Vucetich and the origins of forensic fingerprinting Vucetich compared the fingerprint to those of Rojas. Francisca Rojas had denied touching the bloody bodies….

Story Time - Juan Vucetich and the origins of forensic fingerprinting …but the fingerprint matched one of hers.

Story Time - Juan Vucetich and the origins of forensic fingerprinting Confronted with the evidence, she confessed.

Story Time - Juan Vucetich and the origins of forensic fingerprinting Confronted with the evidence, she confessed.

Story Time - Juan Vucetich and the origins of forensic fingerprinting The first successful use of fingerprint identification in a murder investigation.

Classification Systems The most prominent system in the late 19th cent. was the Henry System created by Sir Edward Richard Henry. The Henry System is still included as part of many electronic systems and taught by the FBI.

Henry Classification System Prints are classified by broad characteristics. All 10 fingers are put into groups of 2 with numerical weights assigned to each group

Henry Classification System Thumb R Index R Middle Ring R Pinky L Thumb L Index L Middle L L Pinky Number 1 2 3 4 5 6 7 8 9 10 Value if whorl is present 16

Henry Classification System If a whorl is present the value is recorded for that fingerprint. If a whorl does not exist then zero is recorded for that fingerprint

Henry Classification System Thumb R Index R Middle Ring R Pinky L Thumb L Index L Middle L L Pinky Number 1 2 3 4 5 6 7 8 9 10 Value if whorl is present 16 Example No Yes

Henry Classification System Next, the Henry Classification Formula is used to find the grouping ratio. The grouping ratio is a unique identifier for categorizing the particular type of fingerprint that the person has.

Henry Classification System The Henry Classification Formula is: The grouping ratio cannot be simplified. For example, 32/32 and 1/1 are both unique ratios.  

Henry Classification System Thumb R Index R Middle Ring R Pinky L Thumb L Index L Middle L L Pinky Number 1 2 3 4 5 6 7 8 9 10 Value if whorl is present 16 Example No Yes  

IAFIS Integrated Automated Fingerprint Identification system (IAFIS) is used by the FBI to store digital prints. It is the largest biometric database in the world, containing records for more than 100 million people. The automated process generates a “hit” list of possible matches then checked by expert

What is included in IAFIS? Each record may include: Criminal history Fingerprints Mug shots Scars and tattoos Physical characteristics height, weight, aliases, hair and eye color, race

Who submits data to IAFIS? The system includes: civil fingerprints; Individuals in the U.S. military; people employed by the federal government. Employment background checks and some firearms purchases also provide information to the system.

Other Forms of Biometrics Eye Scans - both retina and the iris have unique characteristics Retinal scan - they are used in most high security facilities but are too expensive to be widespread Iris Identification Systems - these are used in prisons and increasingly in airports

Other Forms of Biometrics Ear Scans Ears are unique in size shape and structure a camera creates an image of an ear that is then analyzed.

Other Forms of Biometrics Voice Fingerprints frequency, intensity, and other measurements are analyzed to determine whether the tape is authentic Not as definitive as fingerprints or DNA but they do provide supporting evidence DNA Fingerprints we all have unique DNA it can be found in your blood, skin, hair etc. it gets isolated, amplified and transferred via radioactive probes and "fingerprinted"