Fingerprint Analysis

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How are prints created?

Prints are created by natural secretions of water, oils, salts, and dirt in the pattern of the ridges

When do they form?

Form at 10th week of gestation

Where do they develop?

Fingerprint development occurs in the basal layer of skin

Whorl

look like bull's eye

Arches

ridges enter on side and leave other side with rise in the center

Loops

enter and exit from same direction

Patent fingerprints

visible print

Patent fingerprints at a crime scene

Left on smooth surfaces when blood, ink , or other liquid comes in contact with hands and is transferred to that surface

Plastic fingerprint

indentations left in soft material

Plastic fingerprint at a crime scene

Clay,putty,wax

Latent fingerprint

not visible to the naked eye

Latent fingerprint at a crime scene

Caused by transer of oil, sweat, etc.

Made visible (lifted) by dusting or chemical reactions

How can fingerprints be altered?

Damage to the skin or over long periods of work

How can fingerprints be lifted?

through a technique called dusting

what is dusting?

Dust sticks to reside left behind by fingerprints

Tape is used to lift the print and apply it to a card

minutiae patterns

the small characteristics in a person's ridge patterns (ex: hooks, deltas, cores)