Forensic Science Questioned Documents

Forensic Science

Questioned Documents

Questioned DocumentsQuestioned Documents

Any object that contains handwritten or typewritten markings whose source or authenticity is in doubt is considered a question document.


These include:

LettersChecksDriver’s licenseContractsWillsPassportsLottery tickets


Questioned documents may also include writings or markings found on walls, windows, doors, etc.

Questioned DocumentsQuestioned DocumentsThe document examiner must ascertain the authenticity or source of a document through handwriting examination and the use of microscopy, photography, chromatography to note any change or alterations.

The examiner must be able to recognize erasures and overwriting in attempt to change the original meaning of a document.

The examiner must be able to reconstruct charred or burned paper.

Handwriting ComparisonsHandwriting Comparisons

Although no two individuals write exactly alike, there may be resemblances is their general style.As a student learns and practices their handwriting, they are making a conscious effort to copy a standard letter form.The two most widely used methods taught in nearly all fifty states in the U.S. are the Palmer method (1880) and the Zaner-Blosser method (1895).

Palmer Method Zaner-Blosser Method

Handwriting Handwriting ComparisonsComparisons

Unconscious handwriting of two different individuals can never be identical.Several factors, such as, mechanical, physical, and mental functions, make reproduction of another’s handwriting unlikely.Variations of angularity, slope, speed, pressure, letter and word spacing,relative dimensions, connections,pen movement, writing skill, andfinger dexterity are distinguish.

Handwriting ComparisonsHandwriting ComparisonsMargins, spacing, crowding, insertions,and alignment arepersonal habits.

Spelling, punctuation, phraseology, and

grammar individualize each writer.

A final conclusion of comparison betweentwo documents must be based on asufficient number of commoncharacteristics.

Handwriting ComparisonsHandwriting Comparisons

Circumstances may prevent a positive conclusion:

Insufficient number of known handwriting samples are available

Questioned writing may contain only a few words, deliberately written in disguise

Drugs and alcohol can alter writing habits

Collection of Handwriting Collection of Handwriting ExemplarsExemplars

In gathering known writing samples for comparison, or exemplars: Known writing should resembled the questioned document

Should contain some of the words and combinations of letters present

Give the range of natural variations

Should be fairly recent, usually within 2-3 years

Collection of Handwriting Collection of Handwriting ExemplarsExemplars

When handwriting exemplars can not be obtained for comparison, a voluntary submittal from the suspect is requested.To help minimize attempts at deception, investigators can:Require several pages of writingWriting of dictationAllow the writer to sit comfortablyFurnished with pen and paper similar to the questioned documentGive no instructions on grammar or punctuation

There are several mechanical devices and machines a document examiner encounters

Computers TypewritersTypewriter ribbonPhotocopiersPrintersFax machines

Typescript comparisonsTypescript comparisons

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.


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.

Infrared Luminescence Infrared Luminescence examplesexamples


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.

Other Document ProblemsOther Document Problems

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.


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


An examiner may also compare the chemical composition of the ink present in both documents using thin-layer chromatography.Using a hypodermic blunt tip needle, ink can be extracted and analyzed.Usually 10 plugs are sufficient.

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


The paper on which thedocument is written orprinted on is alsoanalyzed by the examiner.

Handwriting sample of George W. Bush


Paper can vary by

Appearance ColorWeight

Watermarks

True watermark Fake watermark

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

Fibers Fillers

Pigments Additives

Non-coated Coated

Handwriting Handwriting IdentificationIdentification

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

of the characteristics found in the known Analysis of the questioned or unknown writing

and determination of its characteristics Comparison of the questioned writing with the

known writing. Evaluation of the evidence, including the

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