Fingerprints and Impressions

Fingerprint

An individual characteristic with a pattern that will remain unchanged for the live of the individual.

Fingerprint ridge patterns

-Arch (Plain,Tented)

-Loop(Radial,Ulnar)

-Whorl(Plain, Central Pocket, Double Loop, Accidental)

What percent of the population has loops?

about 60%

What percent of the population have whorls?

about 35%

What percent of the population have arches?

about 5%

Dactyloscopy

The study of fingerprint identification

What are Dactylograms

another word for Fingerprints

Arches

Simplest ridge pattern characterized by a continuous flow of ridges that enter from one side and exit on the opposite side. No Deltas present.

Delta

Triangular-shaped area where two ridge lines diverge

Loops

A common fingerprint pattern where ridges enter from one side, curve around, and exit on the same side. Typically characterized by one delta.

Whorls

Ridge patterns characterized by circular or spiral arrangements with at least two deltas. If there are more than 2 deltas, it’s accidental

Plain Arch

Tented Arch

flows toward thumbs

Radial Loop

Flows toward pinky

Ulnar Loop

Plain Whorl

Central Pocket Whorl

Double Loop Whorl

Accidental Whorl

Core

Eye

Island

Enclousure

Patent Print

A fingerprint that is visible to the naked eye, often left on a smooth surface when a person touches it. It can be made from substances like blood, ink, or dirt.

Plastic Print

A type of fingerprint left on a soft surface, such as wax or clay, that captures the unique details of the ridges and patterns.

Latent Print

Hidden prints, caused by transfer of oil and other body secretions onto a surface. Can be made visible by dusting powders.

Florescent powder and UV lights

Can help find latent prints on multi-colored or dark surfaces

Magnetic Powder

Can be used on shiny surfaces or plastic surfaces to find prints.

Cyanoacrylate

Fuming method used to develop latent fingerprints

Ninhydrin

Chemical that bonds with the amino acids in fingerprint to produce blue or purple color. Used to lift prints from paper and cardboard.

Determining the brand of a tire found at a crime scene is what type of evidence?

Class Evidence

Tire tracks can tell…

Direction the car went, size of the vehicle, and turning diameter

Tool Mark

Any impression, cut, gouge, or abrasion caused by a tool coming into contact with another object.

CSI must never attempt what when examining tool marks?

Never attempt to fit the suspect tool into the tool mark. Each contact between tool and marked surface may alter the mark and will raise serious questions of evidence integrity.