Questioned Document Examination: Literary Forensics

Familiar to anyone who's watched 'Zodiac', handwriting analysis is a field which is invaluable due to the ubiquity of checks and receipts, and the scarcity of competent forgers. It has many uses as well, from confirming suicide notes to tracing who bought what drugs.

Handwriting analysis is usually made up of three stages, according to the ASTM standard guide for examination of written evidence:

1. Analysis:
   Questioned and known items are analysed and broken down to directly perceptible characteristics. These characteristics are usually:
  - Form : elements comprising the shape of the letters, such as proportions, slants, angles, retracings, connections and curves.
  - Line Quality : The pressure exerted and continuity of the script.
  - Arrangement : Any distinctive punctuation, alignment or formatting.
  - Content : Spelling, phrasing, punctuation and grammar.

2. Comparison:
   The characteristics are then compared to a known standard. A known standard, otherwise known as a writing examplar, is a piece of writing used to compare your sample against. It is either requested or collected. These are complimentary to each other as collected writing is less likely to be altered, but typically has fewer reference characteristics, while you can control the conditions perfectly and shove in as many reference points as you want to a requested piece of writing but it is much more likely to be altered. A combination of both is always a good thing.

3. Evaluation: The characteristics of the pieces of writing are evaluated and cimilarities and differences are compared. The conclusion is drawn from a combination of the frequency and uniqueness of characteristics present.

It is important to note that handwriting analysis is not a perfect science, thus in order to use it in a court of law it would always be advisable to seek peer review. With handwriting analysis there are so many variables and every style is so unique that it is difficult (if not down right impossible) to draw certain conclusions. However it is still fairly reliable, and since almost nothing is certain in forensics that's good enough to make it a useful tool in the forensic scientists arsenal.

Here's a quick example of where the FBI managed to pull a match between the sign off of the baby sitter, and the sign off on a ransom note. The minimal efforts to disguise the writing make this suspect an easy case study.

Thanks for reading everyone, any comments, critiques or suggestions, feel free to comment! If not sit tight until next time!