Chapter 6

Stains and dyes that react with protein

- Amido Black dye - Acid Fuchsin - Acid Yellow 7 - Leuco Crystal Violet

Examination of Crime Scene Shoeprints why do you analyze?

- Identify/eliminate a shoe or type of outsole. - Determine the brand or manufacturer of the outsole or footwear. - Link a suspect to a crime.

General Guidelines for the Recovery of Shoeprints

- Photograph the crime scene - Make crime scene sketches - Remove items containing shoeprint impressions - Take close-up photographs of impressions - Enhance and lift the impression

What chemicals are used?

-Amido Black -DFO (1,8-diazafluoren-9-one) -Fluorescence examination

Footwear Impressions First used to solve a crime in?

1786

Analysis, Comparison, Evaluation, Verification

ACE-V

Ardrox

Chemical dye that is sprayed on a print after it has been super glued and fluoresces under a UV light source.

Integrated Automated Fingerprint Identification System

Designed to expedite manual searching of fingerprint records, with a goal of reducing matching time from months to hours

T/F A black light source used to illuminate a black fingerprint on a white surface is very visible.

F -White light

T/F Digital imaging can keep repetitious patterns on the substrate below the fingerprint

F- Remove, Digital imaging can remove repetitious patterns on the substrate below the fingerprint

T/F A colored fingerprint that appears on a colored surface is much more easier to see.

F- difficult

T/F Chemical treatments used for making latent fingerprints visible often do work on shoeprints.

False - Chemical treatments used for making latent fingerprints visible often do NOT work on shoeprints.

A computer program that applies the mathematical operation known

Fourier transform (FFT)

Bromophenol Blue

Indicates pH

(IAFIS)

Integrated Automated Fingerprint Identification System

Dry origin impressions

Made from the transfer of dry material (dirt, dust)

Wet origin impressions

Made from transfer of wet material (blood, paint)

Two-Dimensional Footwear Impressions

Often made when the sole of the shoe encounters the substrate (hard, smooth surface)

Place a scale ("L" shaped, 13 inches long)

Photographic lighting

Nonblood Shoeprints what is used?

Potassium Thiocyanate (KSCN) Bromophenol Blue

Transfer impression (positive):

Produced from the transfer of material acquired by the shoe sole during prior steps.

Biometrics are an example of:

Security systems • Visas • Mobile applications

Development for print

Small Particle Reagent (SPR) o Suspension of Molybdenum Disulfide in a detergent solution. o Particles adhere to lipid components. o Used to process wet evidence. o Print is photographed and lifted.

Examination of Crime Scene Shoeprints what is the purpose?

SoleSearcher and Solemate

ACE-V

The scientific methodology for the comparison and identification of fingerprints

Statistical Analysis of Randomly Acquired Characteristics

This helps form a perspective view of the uniqueness of the match, and allows a forensic expert to express an opinion about the uniqueness of the match with a perspective that is based on statistics

T/F Developed prints should then be photographed.

True

T/F Fingerprint lifts and photographs should be carefully documented to preserve the chain of custody.

True

T/F IAFIS points out possible matches, but the examiner is responsible for performing the identification.

True

T/F If it is impossible or impractical to ship the object to the crime lab, the latent development techniques should be applied at the scene.

True

T/F In order to individualize, the RACs must match.

True

T/F Methods to make latent shoeprints visible are similar for those used for fingerprints.

True

T/F Objects thought to contain fingerprints should be carefully collected and submitted to the crime lab for examination.

True

T/F Prints are preserved by photographing.

True

T/F Shoe soles are constantly worn away (eroded) unevenly depending on gait.

True

T/F Spraying with luminol may make latent impressions visible if made with blood.

True

T/F Super Glue®, iodine fuming, and black fingerprint powder are rarely used

True

T/F These powders are used to dust paper currency and documents and are sprayed in areas where recurring thefts take place?

True

T/F Use an ALS or camera with barrier filters to accentuate color/reduce color

True

T/F While photographing the print, the examiner exploits the selective absorption of light by different colors on the surface.

True

Lifting Enhanced Shoeprints what is used?

Wide tape • Gelatin lifters (preferred): Clear, flexible, 1-mm thick pads that contain a layer of low-adhesive gelatin

How are areas examined?

With UV Light

Is Potassium Thiocyanate (KSCN) toxic if inhaled?

Yes

Stone (2006)

________________has proposed a probability model for identifying characteristics.

DFO (1,8-diazafluoren-9-one)

a ninhydrin-like analogue that reacts with proteins to give a highly fluorescent, red-colored product that is more sensitive than ninhydrin

Physical developer

a silver based solution used as a substitute for the conventional latent print silver nitrate procedure useful in detecting latent prints on porous surfaces that are wet

randomly acquired characteristics (RAC)

can be cut, scratched, punctured, or torn.

Gentian violet or crystal violet

dye produces a purple color and stains the fatty components of latent prints

Light Amplification by Stimulated Emission of Radiation

effective in locating and visualizing latent prints, as well as other types of physical evidence o trace evidence o biological evidence

Ninhydrin solution

for use with porous surfaces, o paper, cardboard, wallboard, and raw wood

The Henry Classification System

forensic ridge patterns from all 10 fingers into two numbers that are arranged as a fraction.

Biometrics

is a way of authenticating (verifying) the identity of an individual by using fingerprints, palm prints, retinal scans or other biological signatures

The system assigns a __________________ to each finger and a numerical value to fingers that contain a whorl pattern

number

Iodine

one of the oldest methods of visualizing latent prints on porous and nonporous substrates

What forms can fluorescent powder be in?

powder and aerosol forms

Silver nitrate

reacts with chlorides in prints, but not in widespread use

Potassium Thiocyanate (KSCN)

reacts with iron in shoeprints made from the transfer of soil.

_____________ can provide conclusive evidence that will link a suspect to a crime scene, or can show the criminal's movement through the scene.

shoeprints

Amido Black

this stain turns proteins present in blood blue-black

Vacuum metal deposition (VMD):

used for most smooth nonporous surfaces (plastic bags, plastic packaging material) The procedure evaporates gold or zinc in a vacuum chamber, and a very thin film of the metal is deposited onto the latent print, making it visible

Sudan black

used on nonporous articles (glass, plastics, metal); method of choice if the substrate is oily or greasy

Superglue (cyanoacrylate) fuming

used on nonporous surfaces to produce visible prints that are white

Fourier transform (FFT)

used to convert the digital image

Fluorescence examination

using lasers, alternative light sources, or UV lamps on untreated surfaces may yield prints

effective in locating and visualizing latent prints

well as other types of physical evidence o trace evidence o biological evidence