A branch of forensic science called "forensic document examination" employs scientific techniques to ascertain the provenance, authorship, and authenticity of documents. To find forgeries, changes, or other tampering, examiners examine a variety of documents, including typewriting, handwriting, and even markings on other surfaces. They find evidence using specialized tools including microscopes, UV lamps, and electrostatic detecting devices, and they frequently offer expert testimony in court. Handwriting analysis, modification detection, forgery detection, origin tracking, and others are examples of frequent tests. To examine forensic documents, they use instruments and methods like microscopes, ink and paper analysis, electrostatic detection devices (ESDA), and ultraviolet (UV) light. Let's get into more depth about these following.
Types of Evidence Examined
Identification cards, contracts, wills, titles and deeds, seals, stamps, bank checks, handwritten letters, papers produced by machines (such as photocopiers, fax machines, and printers), currencies, and electronic documents are all examples of material that may be questioned. Graffiti and digital signatures may be studied in some situations, but the client should be informed that these kinds of evidence might present challenges.
If the documents were beneath other documents at the time of writing, they may include important impression evidence even though they don't have obvious, distinguishable markings. Reconstructing even burned or torn papers might be beneficial.
Additionally, the investigator may gather writing implements, envelopes, rubber stamps, and office equipment types and makes that the suspect may be in possession of. Evidence for digital documents may even be extracted from electronic signature files' metadata, which includes details on the author and the date of creation.
Collecting the Known and Unknown
Forensic document examiners need known specimens to compare the material under examination to when performing exams. These samples might originate from a variety of recognized sources, including a specific ink producer or device.
Samples of handwriting are often separated into two categories: collected writing specimens and requested writing specimens. Writings that are dictated to the writer by the investigator are known as requested specimens. The writer is attentively watched as these examples are produced in tightly regulated settings. However, writings written by the subject before the study are known as collected writing specimens. Cancelled checks, letters, diaries, signed receipts, medical records, real estate contracts, tax records, and other signed legal papers are all good sources of writing samples.
Personnel Involved in the Analysis
A certified forensic document examiner, ideally a member of a reputable professional organization like the American Society of Questioned Document Examiners (ASQDE) or the American Board of Forensic Document Examiners (ABFDE), should do the analysis. These organizations have different membership standards, but generally speaking, an examiner must have finished a two-year, full-time training course taught by a certified forensic document examiner. Examiners must finish continuing education in order to keep their membership in good standing and their skills up to date.
How and Where the Analysis Is Performed
Examiners of forensic documents can work for government-funded labs or as private examiners in their own labs. Investigators may choose to hire a private examiner or transmit the evidence to a neighboring lab if an agency lacks the capacity to analyze questioned papers.
Forensic document inspection methods and instruments make use of recognized physics and chemical concepts. Microscopes, digital imaging equipment, infrared and ultraviolet light sources, video analysis tools, and specialized equipment such as electrostatic detection devices (EDD) and analytical chemistry supplies are all common features of a crime lab's Questioned Documents unit.
Revealing text from indented impressions ― An Electrostatic Detection Device (EDD), such as the Electrostatic Detection Apparatus (ESDA), may be used to see documents that may include indented impressions that are not apparent to the human eye.
Indented imprints from up to seven layers of paper underneath the original text have been retrieved using this method. As long as the documents are not abused or preserved incorrectly, research has shown that impressions may be effectively visualized from documents up to 60 years old.
identifying page swaps, erasures, obliterations, and changes Using photography and other imaging equipment that employ ultraviolet and infrared light wavelengths, it is frequently possible to detect changes, obliterations, and erasures that are not apparent to the human eye. By taking advantage of differences in how different inks react to different light wavelengths, an imaging device like a video spectral comparator (VSC) may detect writing that has been added using a different ink, edited, or erased using radiation filtered at different wavelengths. For instance, a document with information printed in ink that has faded over time may be improved or processed to look darker and so more readable when exposed to specific light sources and an infrared filter.
Identifying individual dye components ― The chemical makeup of inks on a paper can be ascertained via a process known as liquid chromatography. This method involves dissolving a little piece of the disputed document in a solvent and then analyzing it. One of the document examiner's few harmful methods is this one. The inks are comparable to the International Ink Library, a U.S. Secret Service database that has information on over 9,500 inks produced since 1920.
Typewritten and machine-printed documents Typewritten papers or documents produced by a laser printer, fax machine, photocopier, or ink jet can be traced back to a specific machine or even a specific make and model. It is also possible to identify the printing method used to create papers. The machine in issue should be submitted for inspection, and the examiner should try to get hold of any known standards and accessories from the machine.
Seals and stamps: Documents that have rubber stamp impressions, embossed seals, watermarks, other mechanically produced markings may be submitted for review. Any suspected equipment connected to the questioned document that could have been used in its creation should, if at all feasible, be given to the examiner. Papers, rubber stamps, various substrates, sealing devices (such notary seals), printing equipment, and writing instruments are all included in this category.
Analysis of handwriting ― There are usually noticeable variations when a significant volume of writing from two distinct individuals is thoroughly analyzed. Numerous handwriting traits are taken into account when comparing writing samples, such as word and letter spacing, speed, slant or slope, capitalization, embellishments, pen position, readability, punctuation, letter proportions, and other features.
As an illustration, one individual may make the letter "O" in a clockwise manner, while another might do the same in a counterclockwise manner. One writer may use an upward-moving "arch" shape to construct the letter "M," like to the McDonald's Restaurant sign. Another writer might rather use a "garland" form of the letter, creating it with a "U" motion to mimic the garland on a Christmas tree. The different feature combinations seen in the writing sample as a whole are taken into consideration by document examiners. Examiners often search for characteristics like pauses in the writing's organic flow, potential retouching, or unusual tremors. These might suggest the use of an artificial writing technique (such as disguise or simulation).
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