1 forensic science questioned documents documentation

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Forensic ScienceQuestioned Documents

Documentation

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Questioned DocumentsInvolves the examination of handwriting, ink, paper,

etc. to ascertain the source or authenticityExamples include letters, checks, licenses, contracts,

wills, passports, etc.Topics

Handwriting analysisInk (and pens)Paper (and pencils)ForgeryCodes and Ciphers

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COMPARISONForensic Document Examiner--

involves the analysis and comparison of questioned documents with known material in order to identify whenever possible, the author or origin of the questioned document.

Unfortunately, no federal licensing exists. There is certification through the ABFDE.

Graphologist--attempts to predict character traits from handwriting examination

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Handwriting

Handwriting analysis involves two phases:The hardware--ink, paper, pens, pencils,

typewriter, printersVisual examination

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Handwriting Characteristics

Line Quality Word and Letter Spacing Letter Comparison Pen Lifts Pen Pressure

Lettering Slant Unusual Letter Formation Diacritic Placement Baseline Habits Body Placement

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Handwriting Identification

“ACE”Analysis of the “knowns” with a determination of the

characteristics found in the knownAnalysis of the questioned or unknown writing and

determination of its characteristicsComparison of the questioned writing with the known writing.Evaluation of the evidence, including the similarities and

dissimilarities between the “questioned” and “known” writing.

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Handwriting Analysis

Handwriting Sample of President George Bush

According to Sheila Lowe in her book, Handwriting of the Famous and Infamous, President Bush’s handwriting is “fast and highly simplified in fairly well-organized writing field”.

Is this a forensic document examiner or a graphologist??

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Handwriting Samples

The subject should not be shown the questioned document

The subject is not told how to spell words or use punctuation

The subject should use materials similar to those of the document

The dictated text should match some parts of the document

The subject should be asked to sign the text Always have a witness

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Linguist

Experts that look at the linguistic content (the way something is written) of a questioned document.

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

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Ink

Chromatography--physically separate mixtures of gases, liquids or dissolved.

TypesGas ChromatographyHPLC--high-performance liquid chromatographyTLC--thin-layer chromatographyPaper Chromatography

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Paper Chromatographywith Ink

Two samples of black ink from two different manufacturers run using paper chromatography.

Retention Factor (Rf)

This is a number that represents how far a compound travels in a particular solvent

It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.

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Scientific EquipmentGas chromatograph--separates mixtures on

the basis of their distribution between a stationary liquid phase and a moving gas phase. The written record of the results is called a chromatogram. A typical one will show a series of peaks, with each representing one component of the mixture. The time required to go from the injection out of the column is known as the retention. This allows identification of class characteristics.

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Scientific EquipmentMass spectrometer--an instrument that connects to

the gas chromatograph. The substance to be identified is exposed to a beam of high-energy electrons causing the molecules of the sample to lose electrons and to acquire a positive charge. These positively charged molecules decompose into numerous fragments. These fragments then pass through an electronic or magnetic field where they are separated according to their masses. The unique feature of mass spectrometry is that no two substances produce the same fragmentation pattern, thus producing individual characteristics.

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Paper

WeightColorWater marksAge

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Pencils

LeadHardness Scale--a traditional measure of the

hardness of the "leads" (actually made of graphite) in pencils. The hardness scale, from softer to harder, takes the form ..., 3B, 2B, B, HB, F, H, 2H, 3H, 4H, ..., with the standard "number 2" pencil being of hardness 2H.

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Forgery

Check FraudForgeryCounterfeitAlterations

Paper MoneyCounterfeit

IdentitySocial SecurityDriver’s license

Credit CardsTheft of card or number

Art--imitation with intent to deceiveMicroscopic examinationElectromagnetic radiationChemical analysis

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Codes and Ciphers

Codes--letter combinations or symbols used to represent words or conceptsInterception from terrorists and other war

enemies

Ciphers--a message in which letters or symbols replace the actual letters in the message.

CRAZY CRIMINALSAccording to Point of View, a magazine published

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

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

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

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Used as Evidence

1. Class characteristic--the type of ink may have similar characteristics at the primary and/or secondary crime scene, on the suspect or on the victim. Handwriting may be used to include or exclude a suspect.

2. Individual characteristic--With document analysis, it is difficult to identify to an individual characteristic except with typewriter or printer specific marks.