Indented writing impressions are created from the pressure of the writing instrument as it’s transferred from the primary paper to the sheets underneath. These impressions may not be visible to the naked eye; however, specialized electrostatic equipment can help a Forensic Document Examiner (FDE) visualize indented impressions.
Typical indentation examinations can resolve sequencing issues, determine the source of a document, or provide investigative assistance.
Types of Cases
Indented writing examinations are required on almost all pieces of documentary evidence that goes through the Laboratory. Frequently, indented writing is recovered on investigations of medical charts, anonymous letter cases, ledgers, prison correspondence, notebooks, and diaries. These types of cases usually include multiple pieces of a paper where the writing impressions from the primary paper may be transferred to several layers underneath.
How does an FDE see indented writing?
Because an impression is transferred from the primary page to several pages below, the first step is to use side lighting. Side lighting is used to reveal surface details and allows a FDE to pinpoint areas that may contain impressions and need further processing. Once side lighting is complete, the examiner will move to an electrostatic machine to recover the impressions in a non-destructive way. The impressions below use side lighting to observe impressions.
Case Study: Lucas Helder aka Smiley Face Bomber
Lucas Helder was a college student attending the University of Wisconsin – Stout in 2002 when he began his bombing spree. Planning to plant pipe bombs in mailboxes across the U.S., Helder hoped to complete a smiley face shape. The bombs, filled with nails and BB’s, were rigged to explode upon opening. In all, Helder planted over 18 bombs in 6 states injuring six people before being apprehended in Nevada.
Once apprehended, Helder’s car was processed and several notebooks were submitted for evidence. The notebooks were processed for indented writing and were found to “match” a letter left for one of the victims. The picture below demonstrates the original letter (with a hole where the bomb exploded) and the indented impression lift. The indented writing corresponded to the actual writing on the letter as well as the missing text where the bomb exploded.
Mr. Helder was found incompetent to stand trial and remains incarcerated in the Federal Medical Center in Minnesota.
Should you ever need an examination for indented impressions, my office can walk you through the process and help you recover information you may have thought lost. Please don’t hesitate to call me for a preliminary review at +1 (312) 343-9902.