FORENSICS GUIDE
How document examination works
Document examination asks whether a signature, a handwritten entry or a page is what it appears to be. This guide walks through the work step by step, from the samples you supply to the opinion in the report.
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What is a questioned document?
A questioned document is any document whose authorship, origin or content is in dispute. It might be an agreement that one party says they never signed, a will with a change squeezed into the margin, a receipt whose amount looks different from the rest, or an anonymous letter nobody admits to writing.
The question is usually narrow. Did this person write or sign this? Has anything been added, removed or changed since it was first made? The examiner does not start from who is right in the dispute. The work begins with the document itself and with reliable material to set beside it.
How do I gather good known samples?
Known samples, also called exemplars, are writing or signatures whose author is not in doubt. They are the yardstick for the comparison, so their quality shapes how firm the final opinion can be.
- Collect several samples, not one. Everyone’s writing varies a little, and that natural range only shows up across a number of signatures.
- Choose documents made around the same time as the questioned one. Handwriting drifts with age, health and habit.
- Match like with like: signatures against signatures, block capitals against block capitals, figures against figures.
- Prefer everyday papers signed in the ordinary course of life, such as cheques, application forms and letters, over samples written specially for the case.
- Note where each sample came from and how you know who wrote it.
Samples written on request can help, but people sometimes disguise their writing when they know it will be examined. Material made before the dispute began is usually more telling.
What does the examiner look at?
Line quality
Under magnification, a natural signature flows, with smooth changes of speed and pressure. Hesitation, blunt starts and stops, patched strokes and a shaky line can point to slow copying or tracing.
Letter formation
The examiner studies how each letter is built: its proportions, the connecting strokes, slant, spacing and the order in which the pen moved. These habits are formed over years and are hard to imitate consistently.
Pen pressure
Pressure leaves grooves in the paper and changes in how densely the ink sits. Pressure that is oddly heavy or oddly even can matter, and faint impressions can reveal writing from a sheet that once lay on top.
Alterations under UV and IR light
Two inks that look identical in daylight can respond quite differently under ultraviolet or infrared light. That difference can expose an added figure, overwriting, or an entry that was later covered over.
Paper and page
The paper, staple holes, folds and page order are checked too, for signs that a page was swapped or that parts of the document were put together at different times.
What does the report say?
A document examiner’s report sets out what was received, the methods used, what was seen and the opinion reached. Photographic charts place features of the questioned writing beside the same features in the known samples, so a reader can see the reasons for the conclusion rather than take it on trust.
Opinions are given on a graded scale, not as a bare yes or no. An examiner may say the evidence strongly supports, supports or does not support the proposition that a named person wrote a signature, or that no conclusion is possible. How far the opinion can go depends on the quality and amount of material, including your known samples.
Our reports are prepared for use in legal proceedings and have been relied on by Kenyan courts. Whether evidence is admitted is decided by the court in each case. Before a report is released, the work is checked a second time: findings are peer-reviewed by a senior examiner in line with our standard operating procedures.
What should I do with the original?
The original carries evidence that a copy loses: pressure grooves, small differences between inks, faint impressions and the paper itself. A photocopy or scan can sometimes be examined, but any opinion based on it is more limited.
- Keep it flat in a clean paper envelope or folder, away from heat, damp and direct sunlight.
- Do not staple, punch, fold, laminate or write on it, and do not attach sticky notes.
- Handle it as little as possible, with clean, dry hands, and never trace over the writing or point at it with a pen.
- Do not try any test or treatment of your own. Some can change the ink or the paper for good.
- Keep a short record of who has held the document, when and why.
If someone else holds the original, such as a bank or the other side in a dispute, raise it early. Getting access to it can take time.
Terms in this guide
Questions
Can a forged signature be detected?
In many cases it can, though not in all. An examiner can assess whether a signature fits the person’s known writing or shows signs of simulation such as tracing or slow copying, and states the strength of that opinion.
Can a signature be examined from a photocopy?
Sometimes, but with limits. A copy hides pressure, fine detail in the stroke and differences between inks, so the opinion is usually more cautious than one based on the original.
How many known signatures does an examiner need?
There is no fixed number. Several genuine signatures from around the same period give a far better picture of natural variation than one or two.
How long does a document examination take?
It depends on the case; we give an estimate before work begins.