Positive forensic identification occurs when an unknown sample is determined to match a known sample in the opinion of the forensic analyst. Forensic analysts compare known samples against unknown “subject” samples and evaluate the probability of a positive match. Results depend on the quality of the unknown sample and the number and variety of original known samples used for comparison.
Handwriting Analysis
Most people write differently from each other, with differing stroke directions, unique pressure areas in each letter and in varying sizes. People also write with dissimilar cursive structures, serif variables, spacing and other specific handwriting characteristics. Consequently, forensic analysis may reveal the identification of the author, even when the writer has attempted to disguise their writing.
Ideally, analysts require ORIGINAL documents since photocopies do not allow us to microscopically measure indentation, which is an indicator of pen pressure. If only photocopies are available, it is still possible to make a comparison, but an expert’s opinion cannot be as definitive. No expert will testify to a “definite match” in court based on comparing photocopies – opposing counsel will invalidate such a claim.
Analyzing original documents can also reveal indentations on the substrate. For example, if the sample was underneath another piece of paper written upon by the author, indentations can be detected and may provide valuable information as to the identity of the author.
Sample documents for comparison may be located in human resources files, health insurance paperwork, work files, letters etc. The opinion of the forensic examiner can be more definitive if a large number of varied original samples are provided for comparison against the subject document.
Fingerprint Analysis
Fingerprints are impression made by the papillary ridges on the ends of the fingers and thumbs. Fingerprints afford an infallible means of personal identification because the ridge arrangement on every finger of every human being is unique and does not alter with growth or age.
Fingerprints are caused by pressure or friction between the fingers and the surface with which they are in contact. Like an ink stamp, the ridges cause contact patterns to form on the surface. Each ridge of the outer skin is dotted with sweat pores and is anchored to the inner skin by a double row of peg like protuberances, or papillae.
Consequently, fingerprints remain the most common form of human identification in the world today. An unknown subject print is compared against known, “latent” samples. Identifiers in each fingerprint are compared and identification can be definitive if the samples are complete.
If you have an item that you wish to have examined, store it in a PAPER bag if possible and be sure to limit the number of people who touch it. If other people have touched the subject item to your knowledge that does not make it useless, but it means that we will need the fingerprint samples of the people who were known to touch it. We can then eliminate those prints from consideration.
The more known samples you have, the easier it will be to make a definitive determination.
Some items hold fingerprints well and others do not. Generally, paper is not a particularly good substrate for holding fingerprints, although we have managed to pull prints from letters and envelopes. The deposit of a fingerprint depends very much on the amount of oil in the skin – higher oil secretion levels provide more complete fingerprints.
If you have an item to analyze, secure it first with a witness to evidence the chain of custody, which will likely come up in court if the matter ever gets that far. Then call us before you start wrapping, bagging or mailing anything. A few extra steps at this stage may be critical to preserving the fingerprints.
DNA Analysis
Many crimes are now being solved purely on DNA evidence alone - DNA exists in hair, saliva, dandruff, and every part of our bodies. Artus Group forensic analysts conduct DNA analysis, conducted by pioneers renowned in the field.
The first step is to determine if a DNA profile can be obtained from the unknown sample, to obtain a “profile”. If tests prove positive, analysts will then compare the unknown DNA subject sample against known DNA samples provided by the client. Known samples can be provided as saliva and hair etc, but please call us before taking DNA samples.
DNA analysis can resolve serious crimes, can determine paternity and inheritance suits, can reveal the sender of hate mail and can be a critical component in criminal and non-criminal investigative methodology.
Voice Analysis
Our spectrographic voice analysts compare unknown subject voice recordings to known voice samples provided by the client to evaluate the possible match of identifying features. Again, as many good quality known voice recordings as possible are required to compare against the unknown subject sample. Subject and sample recordings can be digital or analog.
Statement Analysis
Forensic Statement Analysis is a subjective interpretation which has proven vital in assessing levels of threat, deception and risk. The Artus Group uses one of the leading Statement Analysts in the world to evaluate documents to establish a profile or a framework for identity of the author.
The analyst looks for the quality of the spelling and grammar, looks for certain words and phrases used by certain demographic groups and searches for expressions, words or colloquialisms which pertain to geographic and social identities. From these identifiers, the analyst pieces together a profile of the author (male, female, education level, approximate age range and the geography of upbringing and life experience).
Based on a significant career of evaluating documents ranging from terrorist threats to murder and serial killer confessions, the analysts then evaluates the structure of the words to determine threat levels, levels of deception and risk.
Although Forensic Statement Analysis can not identify the author, it can often identify an accurate profile of the writer and can evaluate risk, which can both be invaluable to the client. The results are often startling.
Please call us to discuss forensic investigations in more detail.
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