Criminalistics: An Introduction to Forensic Science Chapter 18 PDF

Criminalistics: An Introduction to Forensic Science Chapter 18 Document Examination Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Educati...

Criminalistics: An Introduction to Forensic Science Chapter 18 Document Examination Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Introduction (1 of 2) Any object with handwriting or print whose source or authenticity is in doubt may be referred to as a questioned document. Document examiners apply knowledge gathered through years of training and experience to recognize and compare the individual characteristics of questioned and known authentic writings. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Introduction (2 of 2) For this purpose, the gathering of documents of known authorship or origin is critical to the outcome of the examination. The uniqueness of handwriting makes this type of physical evidence one of the few definitive individual characteristics available. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Character of Handwriting (1 of 6) Document experts continually testify to the fact that no two individuals write exactly alike. Many factors comprise the total character of a person's writing. The early stages of learning handwriting are characterized by a conscious effort to copy standard letter forms. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Character of Handwriting (2 of 6) However, as writing skills improve, nerve and motor responses associated with the act of writing become subconscious. The unconscious handwriting of two different individuals can never be identical. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Character of Handwriting (3 of 6) Variations are expected in: – Angularity – Slope – Speed – Pressure – Letter and word spacing – Relative dimensions of letters – Connections – Pen movement – Writing skill – Finger dexterity Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Character of Handwriting (4 of 6) Other factors to consider include the arrangement of the writing on the paper: – Margins – Spacing – Crowding – Insertions – Alignment Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Character of Handwriting (5 of 6) Can be personal and help to individualize the writer: – Spelling – Punctuation – Phraseology – Grammar The writing style of one individual may be altered beyond recognition by the influence of drugs or alcohol. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Character of Handwriting (6 of 6) No single handwriting characteristic can in itself be taken as the basis for a positive comparison. The final conclusion must be based on a sufficient number of common characteristics between the known and questioned writing samples. There are no hard and fast rules for a sufficient number of personal characteristics; it is a judgment call made by the expert examiner in the context of each case. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Handwriting Exemplars (1 of 2) The collection of an adequate number of known writings (exemplars) is most critical for determining the outcome of a handwriting comparison. Known writing should contain some of the words and combination of letters present in the questioned document and be adequate in number to show the range of natural variations in a suspect's writing. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Handwriting Exemplars (2 of 2) The writer should never be shown the questioned document or be told how to spell certain words or what punctuation to use. The writing implement and paper should also be alike. The writing of dictation several pages long may serve to minimize attempts at deception. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Typescript Comparisons The two requests most often made of the examiner in connection with the examination of photocopier, fax, and printing devices are: – Whether a particular suspect printing device can be identified as having prepared the questioned document – Whether the make and model of the printing devices used to prepare the questioned document can be identified Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Characteristics from Use (1 of 2) As is true for any mechanical device, use of a printing device will result in wear and damage to the machine's moving parts. These changes will occur in a fashion that is both random and irregular, thereby imparting individual characteristics to the printing device. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Characteristics from Use (2 of 2) The document examiner has to deal with problems involving business and personal computers, which often produce typed copies that have only subtle defects. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Digital Technology (1 of 2) In the cases of photocopiers, fax machines, and computer printers, an examiner may need to identify the make and model of a machine or to compare a questioned document with test samples from a suspect machine. A side-by-side comparison is made between the questioned document and the printed exemplars to compare markings produced by the machine. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Digital Technology (2 of 2) Examiners compare transitory defect marks, fax machine headers, toner, toner application methods, and mechanical and printing characteristics. For faxed documents, a header known as the transmitting terminal identifier (TTI) can serve as an important point of comparison. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Alterations, Erasures, and Obliterations (1 of 4) Document examiners must deal with evidence that has been changed in several ways, such as through alterations, erasures, and obliterations. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Alterations, Erasures, and Obliterations (2 of 4) Erasures by rubber erasers, sandpaper, razor blade or knife to remove writing or typing disturbs the fibers of the paper and are readily apparent when examined with a microscope under direct light or with side lighting. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Alterations, Erasures, and Obliterations (3 of 4) If an alteration is made to a document with ink differing from the original, it can sometimes be detected due to differences in the ability of ink to absorb infrared light. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Alterations, Erasures, and Obliterations (4 of 4) Obliteration of writing by overwriting or crossing out to hide the original writing can be revealed by infrared radiation, which may pass through the upper layer of writing while being absorbed by the underlying area. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Other Problems (1 of 3) Infrared photography and reflecting light at different angles are sometimes successfully used to reveal the contents of a document that has been accidentally or purposely charred in a fire. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Other Problems (2 of 3) In certain situations, indented writings (partially visible depressions underneath the visible writing) have proved to be valuable evidence. It may be possible to determine what was written by the impressions left on a sheet underneath the one on which the original writing was done. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Other Problems (3 of 3) Applying an electrostatic charge to the surface of a polymer film placed in contact with a questioned document will visualize indented writings. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Digital Imaging Processing An image can be scanned by a scanner or a digital camera and converting the image by computer into an array of digital intensity values called pixels. Once the image has been digitized, an image editing program can be used to make adjustments such as lightening, darkening, color, and contrast controls. Using a photo editor on a digitized image can reveal information that has been obscured. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Ink and Paper Comparisons (1 of 2) A study of the chemical composition of the ink used on documents may verify whether or not known and questioned documents were prepared by the same pen. The paper itself may be analyzed. A nondestructive approach to comparing ink lines is accomplished with a visible light microspectrophotometer. Thin-layer chromatography is also suitable for ink comparisons. Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved Copyright Criminalistics, 13e Saferstein/Roy Copyright © 2021, 2018, 2015, 2011 Pearson Education, Inc. All Rights Reserved