1

Computer AnalysisComputer Analysis

2

LinguistLinguist

Language that is used can help to Language that is used can help to establish the writer’s age, establish the writer’s age, gender, ethnicity, level of gender, ethnicity, level of education, professional training, education, professional training, and ideologyand ideology..

3

There are several mechanical devices and machines a document examiner encounters

Computers TypewritersTypewriter ribbonPhotocopiersPrintersFax machines

Typescript ComparisonsTypescript Comparisons

4

Document AlterationsDocument Alterations ObliterationsObliterations——removal of writing by removal of writing by

physical or chemical means can be physical or chemical means can be detected by:detected by: Microscopic examinationMicroscopic examination UV or infrared (IR) light UV or infrared (IR) light Digital image processingDigital image processing

Indentations Indentations can be detected by:can be detected by: Oblique lightingOblique lighting Electrostatic detection apparatus (ESDAElectrostatic detection apparatus (ESDA))

5

Alterations, Erasures, and Alterations, Erasures, and ObliterationsObliterations

The most common way to alter a document is erasure, either using an Indian rubber erasure, or with chemicals.

These changes can be seen under a microscope using direct or side lighting.

6

Alterations, Erasures, and Alterations, Erasures, and ObliterationsObliterations

Examiners often use Infrared Luminescence.When some inks are exposed to blue-green light, they absorb the radiation and reradiate infrared light, making any alterations visible with infrared sensitivefilm.

Infrared luminescencecan also reveal writing that has been erased.

7

Infrared Luminescence Infrared Luminescence examplesexamples

8

Alterations, Erasures, and Alterations, Erasures, and ObliterationsObliterations

Obliteration is the act of blotting or smearing over a writing or printing to make the original unreadable.

The contents of a charred document can sometimesBe revealed through infrared photography.

9

Other Document EvidenceOther Document Evidence

Indented writings are the impressions left on papers positioned under a piece of paper that has been written on.

Sometimes the document is readable

with oblique lighting, or angling thedocument againstthe light.

10

Other Document ProblemsOther Document Problems

Electrostatic charge can beapplied to the surface if theindented document, thenlayered with toner powder to produce an image.

11

InkInk

ChromatographyChromatography--physically --physically separatesseparates mixtures of gases, liquids or mixtures of gases, liquids or dissolved solids.dissolved solids.

TypesTypes Gas ChromatographyGas Chromatography HPLC--high-performance liquid HPLC--high-performance liquid

chromatographychromatography TLC--thin-layer chromatographyTLC--thin-layer chromatography Paper ChromatographyPaper Chromatography

12

13

Specialized LigthingSpecialized Ligthing

14

PaperPaper

DifferencesDifferences Raw materialRaw material WeightWeight DensityDensity ThicknessThickness ColorColor WatermarksWatermarks AgeAge FluorescenceFluorescence

True Watermark

Forged Watermark

15

Other Document ProblemsOther Document ProblemsPaper examined under a microscope can reveal:

Fibers Fillers

Pigments Additives

Non-coated Coated

16

EvidenceEvidence Class characteristicsClass characteristics may include may include

general types of pens, pencils or general types of pens, pencils or paper.paper.

Individual characteristics Individual characteristics may may include unique, individual include unique, individual handwriting characteristics; trash handwriting characteristics; trash marks from copiers, or printer marks from copiers, or printer serial numbersserial numbers..

17

CRAZY CRIMINALSCRAZY CRIMINALSAccording to Point of View, a magazine According to Point of View, a magazine

published by the Alameda county District published by the Alameda county District Attorney’s office, a guy walked into an Attorney’s office, a guy walked into an Oakland bank and handed the teller a Oakland bank and handed the teller a note reading, note reading, “this is a stikkup. Hand “this is a stikkup. Hand over all yer money fast.”over all yer money fast.”

Guessing from this that the guy was no Guessing from this that the guy was no rocket scientist, the teller replied, “I’ll rocket scientist, the teller replied, “I’ll hand over the cash as long as you sign hand over the cash as long as you sign for it. It’s a bank policy that all robbers for it. It’s a bank policy that all robbers have to sign for their money.”have to sign for their money.”

The guy thought this over, then said “Uh, I The guy thought this over, then said “Uh, I guess that’s OK.” He signed his full name guess that’s OK.” He signed his full name and address. That’s where the cops and address. That’s where the cops found him a few hours later.found him a few hours later.

18

More aboutMore aboutDocument AnalysisDocument Analysis

For additional information about For additional information about document and handwriting analysis, document and handwriting analysis, check out Court TV’s Crime Library at:check out Court TV’s Crime Library at:

lwww.crimelibrary.com/criminal_mind/forensics/literary/1.htmlwww.crimelibrary.com/criminal_mind/forensics/literary/1.htm

Or forgery cases at:Or forgery cases at:www.crimelibrary.com/criminal_mind/scams/lincoln_forgers/index.htmlwww.crimelibrary.com/criminal_mind/scams/lincoln_forgers/index.html