Fingerprinting Quiz 2

CSI Fingerprint (What to look for)

Before the touch:

-Donor (the person who left the print behind, is their print smudged)

During the Touch:

-Substrate (The item that the person touch, what texture, is it wet etc)

After the touch:

-Environment (Did it rain, was it humid and the fingerprint evaporated etc)

Common powder use in crime scene

-Black powder is the most common

-But there are other powders, magnetic, biocromatic, colored and fluorescences

Different types of prints

-Latent Prints Barely/invisible print

-Patent Prints - visible prints (in blood, in liquid)

-Plastic Print - Print impressed into something like butter

Types of Evidence

Porous --> Liquid able to seep in

Non-Porous-Items that do not absorb water

Techniques for porous

-Ninhydrin, add heat and humidity to speed up the process

* Turns purple, Ruhemann purple

-DFO (1,8-Diazafluoren-9-one) (MUST memorize full name)

Use this first before -Ninhydrin

*It is a fluorescence liquid that you dip it in and use a ALS to see the print

-Indandione used to fluorescent the print

-Zinc-Cloride → only use if ninhydrin was used because it is used to fully develop a ninhydrin print

-Physical development → last used because it is destructive but good for wet prints. It goes through a malic acid pre-wash, followed by a time in a PD solution and water bath.

Techniques for non-porpous

-Superglue fuming

*Cyanoacrylate ester fuming (CAE) is another name for superglue fuming (need to know how to spell)

-Dye Stains (Look at it under ALS)

-Powders

First thing to do for both porous and non-porous is...

Visual Examination

How to items fluorescent

With dye stains, when the print and dye stain is exposed to the light source, the energy of the light is absorbed, causing the electrons to get excited. As they get excited they will rise to a higher state. But they cannot maintain this and must return back down to their normal state.

This takes place by the electrons having to release energy. This release takes place in the form of light

Stokes Shift

A filter to help to actually visualize the print

There are some items that do not fall into either category of porous and non-porous

-Semi-pourous (Like a sheet of paper with a film over it)

-Another is tape

*Tape, process the non-sticky side first then sticky side

Bloody Prints

-One of the primary chemicals for developing latent prints is Animo Black

-Applied by dipping or spraying the item

What to do before testing items

When using chemicals on the evidence, test the chemicals before placing them on the evidence to ensure it works

Henry Classification

A system of fingerprint classification named for Sir Edward Richard Henry (1850-1931).

The System consisted of six parts

Primary

Secondary

Sub-Secondary

Major

Key

Final

Primary

-Looks at whorls only

-Each box is assigned a value

-Even Fingers in numerator

-Odd numbers in the denominator

-(If no whorls then 1/1)

Secondary

-Deals with the index fingers

-Fingers 2 and 7

Will consist of letters instead of numbers

A (Plain Arch), T(Tented Arch), R(Radial Loop), U(Ulnar loop), or W (Whorl)

Sub-Secondary

-Deals with the index finger, middle and ring

-Fingers 2-4 (numerator) 7-9 (denominator)

-Will consist of letters I, M, O (if a whorl is present)

-Loops is present then use cheat sheet

-Arches boo them

Major

-Looks at thumbs

-Will either be S, M, L (Loops)

-I, M, O)

-If arch then boo them

Key

-Only numerators

-First loop and use ridge count

-No pinkies

Final

-Looks at pinkie fingers

-Only loops

-If right pinkie (numerator) is not a loop, move to the left pinkie (denominator)

What sequence of latent print development techniques is used to develop prints from porous materials?

DFO, Ninhydrin, Physical Developer

Iodine vapor is physically absorbed by latent fingerprint deposits and then __________ quickly after development.

Fades

The development of DFO-treated prints may be accelerated with the use of:

Heat

Oldest and least sophisticated method of fingerprint collection is:

ninhydrin

superglue

gentian violet

photography

brush and powder

Brush and powder

When developing prints, it is important to use every method (reagent) in the sequenced chart in order to develop the most prints.

True

False

True

What does Physical Developer (PD) generally react with?

Lipids

Name two sticky-side techniques for processing tape

Wetwop (Sticky side powder)

Gentian Violet (Crystal Violet)

Why is Physical Developer used last in the processing sequence?

It goes through a prewash that washes away amino acids and proteins

Parts of Palm

Parts of feet