By The Forensic Experts Group
Stamps are commonly used to authenticate official documents or demarcate an area for a signatory. Documents on which stamp impressions are typically present include business contracts and agreements, quotations and sales invoices, payment or salary vouchers, and passports.
TYPES OF STAMPS
There are three main kinds of stamps that are commonly used to impart stamp impressions onto documents:
- traditional rubber stamps
- self-inking stamp
- pre-inked stamps.
Traditional rubber stamps require the use of an inking pad to manually coat the stamp die with ink; pre-inked and self-inking stamps do not. Instead, when a stamp impression is made using a self-inking stamp, the mechanical action of pressing the stamp down causes the die to retract back and forth against the stamp’s internal ink pad. Pre-inked stamps on the other hand have a reservoir of ink behind the stamp from which the ink seeps through.
FORENSIC ANALYSIS OF STAMP IMPRESSIONS
In cases involving questioned documents, besides determining the authorship of a signature or handwritten entries, the forensic scientist may also examine other elements present on the document such as its printed contents and stamp impression(s) for signs of anomaly. When a company stamp impression is present on the same page as the disputed signature, the duality of both elements is synergistic in their probative value for indicating signs of fraud or forgery.
Case study 1: The authenticity of an official invoice bearing the client’s company stamp and signature was disputed. The client claimed that he had never seen the disputed invoice before. TFEG was able to show that the disputed stamp impression and signature were in fact a product of a cut-and-paste manipulation.
In the two cases below, TFEG examined documents on which stamp impressions were called into question. From our analysis, the stamp impressions were determined to not be authentic.
Case study #2: In a High Court civil suit involving disputed sales and purchase agreements and other business documents, TFEG was engaged to examine the authorship of the signatures on the disputed documents. Unfortunately, the design of the disputed signatures was different from those of the specimen signatures, rendering them not comparable. TFEG recommended that the authenticity of the company stamp impression accompanying each disputed signature be examined. Upon comparison with specimen stamp impressions made using the stamp belonging to the company, the disputed stamp impressions were found to be different, providing objective evidence that the disputed documents were fraudulent.
Case study #3: An individual was alleged to have signed an official document on a certain date, which he disputed. He claimed that he had travelled overseas on that particular day and could not have signed that document. Forensic analysis of the immigration stamp impressions in his passport revealed that the stamp impressions of the date in question were not authentic.
HOW TFEG CAN HELP YOU
If you have a document bearing a stamp impression and you suspect the document of being tampered with, get in touch with our forensic scientists and let us advise you on your best course of action.
Please call us at 6459 0494 or email us at [email protected].
