Document Analysis Chapter 18

Forensic science is a thoughtful and yet not dull, class. Write this sentence: Forensic science is a thoughtful and yet not dull, class.

Now… write it a second time: Forensic science is a thoughtful and yet not dull, class.

Now… Try to disguise your handwriting by writing the same sentence Which letters did you change? Did the slant of the letters change? Did the size of a particular letter change more than others?

Questioned Documents Questioned documents are any document that has an issue raised or is part of a criminal investigation Examine handwriting, paper type, ink type Handwriting gives individual characters Ink and paper yield class characters

Handwriting Analysis General Style—style taught in particular locations; Palmer method and Zaner- Bloser method are most common in US During learning, styles look similar, but as mature, styles become individual Variations—Since handwriting in adults is unconscious, mechanical, physical, and mental functions affect handwriting Many individual characters in adult handwriting

Handwriting Challenges Need many known samples to make a definitive handwriting match; less effective with fewer standards Difficulties arise when questioned document has only few words Difficulties arise when person purposely tries to mask handwriting style in drafting document

Handwriting Exemplars Need many exemplars Natural variations exist between samples from same person; many exemplars allow for seeing natural variations For exemplars, writings should be done sitting comfortably, should not know about document, use similar pen and paper to crime scene, dictated sample should contain many same words as questioned document, repeat at least 3 times, and signatures should be taken from other signed documents http://www.youtube.com/watc h?v=yooWnss2wUI

Typescript Comparisons Can be used to determine make and model of photocopier, printer, or fax machine Takes 10 exemplar samples from each machine to compare to questioned document Debris on the glass can yield marks that can be matched to a set printer For faxes, the transmitting terminal indentifier is printed in different type and can be matched more closely Microscope analysis is done to match printer samples Typewriters—can determine make and model from sample analysis

Document Problems Erasure—removes words; impressions can be used to recreate lost words Obliteration—chemically removing words from documents Infrared luminescence can be used to reform the chemically obliterated items Crossing-out; often close analysis can recreate words Charred documents— different angle analysis can make charred areas visible

Indented Writings Marks are made on paper positioned under the paper that was written on Can be analyzed under oblique or side lighting Electrostatic polymer and toner powder allows for visualizing indented writings

Ink and Paper Comparison Figure out chemical composition of ink; microspectrophotomer; chromatography Paper fibers can be analyzed to identify source; paper content, color, texture, thickness, weight, watermarks can all be analyzed http://www.youtube.com/w atch?v=jzf0stGQhrk http://www.youtube.com/w atch?v=fLc36wxLrVI