~ Fingerprints are taken in a controlled setting such as arrest

~ Elimination prints are the prints of those people who had access to the item or area/~ There are several ways to take emilination prints
~Major cases prints are inked impressions of all ridge detail present of the finger and palm

Latent Prints

(Non Visible)

3 Causes of invisible Prints:

   1.)Salt   2.)Oily Matter   3.)Amino Acid

~ these prints need somthing to make them visible such as powder on new prints

~ must you the correct order of chemicals incase one does not work

Pantent Prints

(Visible)

~These occur when the fingers have been coated with blood, grease, dirt or dust

~They could also be found on highly reflective surfaces

~always retain object when possible

Plastic

or

3 Dimensional prints

~ These are fingerprints that are left in tacky or a semi solid substances such as putty, clay, butter or soap

~Take a picture of the item and then take it with you.

Value

OF

Latent Prints

~ Identification of suspects

~ Elimination of Suspects

~ Link and Actor to multiple scenes

~ Possible Defense - person had legitmate access must check to make sure they indeed had access

~ Must consider all items as possible source of latent prints

~ Never assume you cant get a print off an object

~ Always photograpgh everything

~ Photograpgh then lift

~ Photograpgh in between tries

~ Photograpgh at every stage

Variable

Affecting

Latent Prints

~ Weather   ~ Excessive Water

~ More Textured ~ Harder to get prints but not impossible

~ Smudging due to movement

~ Pressure Applied   ~ Gloves

~ Removing latent prints can cause damage to the oject

~Age or prints cannot be determined but can last a long period of time if well protected

Types

of

Surfaces

Porous

and

Non-Porous

Non-Porous

Surfaces

~ Print lies on the top of the surface and is very fragile Metal, glass, finished wood, polished leather

~ Visual inspection- looks for prints on an object to be printed using oblique lighting

~Dye Stains - Follows superglue process always use light source and goggles

~ Powders - black, gray, fluorescents, magnetic, a variety of other colors

Useing

Powder to Develop

Prints

~ Use powder and brush ends only

~ Use very small amounts of powder 

~ Be very gental and use a twriling motion

~ Lifting Procedure:

    ~ Blow excessive powder off

    ~ Determine size of print to determine type of lifter

Non-Porous

How to preserve the Print

~ Photography

~ Lifting the Print

~ Preserve the original object

~ casting material ( mikrosil, roll in glue)

Identifying

the Lift

~ Initials of Officer

~ Place and time

~ Exact Location of the print

~ Small sketch

~ Lift number

~ Remember this is evidence and must be treated as such

Common

Mistakes

For

Lifting Prints

~ To much powder - Less can be more- Remember you can always add more but you cannot take away

~ To much pressure

~ Air bubbles when lifting

~ Not taking your time

~ Not using common sense

~ Wet or sticky items

~ Must follow proper order of chemicals

~ First visually inspect the item and use an laser or alternate light source

~ Chemical Order:

   Iodine-DFO-Ninhydrin-Physical Developer-Silver Nitrate

With Iodine - always photograpgh print could disappear at anytime.

Two

Dimensional

Foot Impressions

~ 2 Dimensional - Usually transferred or deposited indoors

-Usually left at the entry or exit points

-Usually found on hard surfaces such as wood, tile or   window sills

-Same tools and tecquniques are used to recover foot impressions

-Many times these are overlooked at the crime scene

-Train yourself to look down

Three

Dimensional

Foot Impressions

~ Foot impressions usually found outdoors and are usually casted with something like a dental stone or mikrosoil

~ Always photograpgh prints at everystage of all footprints

Foot Impressions

General

Information

~ Equiptment good to have knee Pads

~ They could be anywhere from floor to ceiling and anwhere in between

~ Follow same process for lifting footprints as fingerprints

~ Static is your enemy

~ may need to overlap tape to cover whole print

~ Lift print at a 45 degree angle

~ Gel lifters are good for lifting prints

~ Squgee and pencil good for getting out air bubbles

Packaging

Of

Foot Impression

~ Date, Case #, Person Making Lift, Location of Lift

~Ship package in;

 - Large glassine bag

 - paper envlope

 - Seal with evidence tape

Three

Common

Guns

1. Single Shot

2. Revolver

3. Semi-Automatic

Firearms

Identification

~ Properities of evidence that can be associated only with a group and not with a single source

~Starts as class and turns in to individual

~ Properties of evidence that can be attributed to common source with an extremely high degree of certainty

~ Makes the item differnt from others in the same class

~ A chemical agent used to develop latent fingerprints on porous materials by reacting with amino acids in persperation

~ Protein material

~ The impression of the friction ridge on the skin surface of the last joint of the fingers and thumb

~ 100 Ridge characteristics in a complete print

~ Twins have the same DNA but different prints

~ Fingerprints are always objective

Automated

Fingerprint

Identification

System

~ Compuer system that holds fingerprints

~ Uses automated scaning device that converts the image of a fingerprint into digital minutiae that contain data showing ridges at their point of termination (Ridge ending) and the branching if ridges into two ridges (bierfrication)

~ Allows prints to be stored in the form of digitally geometric patterns

~ Controlled by the FBI

~ Computer matched print in the matter of seconds then is analyzed by a fingerprint expert

Patterns

of

Fingerprints

~ Loop 60-65% of prints

   - Look for the Lake with the river flowing in to it

~ Whorl 30-35% of prints

   - Look for the target bullseye

~ Arch 5% of prints

   - Think riding a bike up hill

Live

Scan

~ An inkless device that captures digital images of fingerprints and palm prints and electronically transmits them to AFIS

~Done on glass platen, still needs to analyzed by experts/the human eye

Reflecting

Ultraviolet

Imaging System

(RUVIS)

~Detects the prints in its natural state by aiming UV light at the surface suspected of containing prints

~ Can just hold up to see prints/ they may fluoresce

~ The spiral grooves formed in the bores of a firearm barrel that impart spin the projectile when it is fired

~ Cut into the bore of a barrel of a firearm during production

~ Causes bullet to spin

~ Rifiling Pattern - siminlar to throwing a football

~ rifiling impression on bullet matches rifling patter in barrel, measure both rifiling on bullet and firearm to get match

~ Also lookat lands a grooves and width to find a match

Difference

Between 

Revolver and Pistol

~ Revolver has a rotating cylinder

~ Pistol loads it has a magazine

~ individual charastic from marks, nicks and flaws

~ These are impressed into the metal as the negatives of minute imperfections found on the rifiling cutters surface or they are produced by minute chips of steel pushed against the barrels inner surface

The diameter of the bored of a riffled firearm, usually expressed in hundredths of an inch or millimeters

Example: .22 caliber = 9 millimeter

Barium

and

Antimony

~ Pick up by the grips or edge trigger guard

~Use two fingers and do not touch another other part of gun

~ Always treat it like it is loaded

~ Metal Alloys

~ Lead

~ Copper

~ Brass

~ Aluminium

Rate

of

Twist

~ angle at which the rifiling is cut in to the bullet or barrel is determined by:

Size or caliber, number of lands or grooves, direction of pitch or twist, or sixe of the lands and grooves

~ Individual Characteristics

~ Must look very close under a microscope and get the striations

~ New tools have les individual marks

~ Hardest part is making the marks visible to the eye

~ Photograpghing tools is hard

Tool

Mark

Facts

~ Usually used in burglaries

~Always photograph first

~Individual characteristics can determine tool used

~look for pry marks

~ Always get print if possible before casting

~If a suspect is stopped with a duffel bag full of tools get posession of those tools

~ the mechanism in a firearm that withdraws a cartridge or fired case from the chamber

~ Developed before birth

~ they are raised pieces of skin found only on the palm and planter side of the hand and feet

Order of

Chemical Use For

Porous Items

1. Iodine

2. DFO

3. Ninhydrogen

4. Physical Developer

5. Silver Nitrate

Three

Levels of

Ridge Detail

1. Pattern type and formation of ridges

2. Individual and class characteristics of intervening ridges

3. The shapes and sives of ridges, minutia and pores

Minutiae

(Ridge Characteristics)

~ Inked

~ Latent

~ Visible or Patent

~ Plastic or 3 Dimensional