Technique Could Find Anthrax Sender
L O N D O N, Nov. 1 -- Top forensic document investigators in the United States and overseas believe whoever sent the anthrax-laced letters in the United States may have delivered evidence that could help agents track down who's responsible.
Using a 25-year-old technique known as electrostatic detection, FBI investigators can recover handwriting impressions made on a piece of paper overlying the letters or envelopes, says Audrey Giles, a former Scotland Yard investigator who runs a document laboratory outside London.
"You might very luckily come up with an address, part of an address a telephone number, a note," says Giles
While there are no guarantees, the possibilities for this forensic technique hold promise, say experts.
"If people became careless, or if one of the letters came from a notepad, there's a good chance the FBI will find a clue that will lead them to the source," says Paul A. Osborn, a forensic document examiner in New Jersey who has seen copies of the letters.
Highly Sensitive
The Electrostatic Detection Apparatus (ESDA) Giles demonstrated for ABCNEWS creates a small static charge over any impression left on a piece of paper. Tiny particles similar to photocopier toner are then sprinkled over a protective layer of film.
"In fact, the whole process is similar to what goes on in a photocopier," Giles point out.
In a matter of seconds these black particles are attracted to the charge, revealing traces of writing — just as a decoder pen reveals invisible ink.
The ESDA is highly sensitive, detecting impressions left as many as three or four pages down.
Osborn says there is a good chance at least one letter included with an anthrax sample was written on notepad, based on copies of letters provided him by media organizations.
Scanning for Clues
Video spectral equipment, which roughly resembles a desktop computer scanner, could be used to compare the ESDA results.
Using two handwriting samples she recovered with the ESDA, Giles scanned these into a Video Spectral Comparitor or "VSC 2000," to show how the FBI could enlarge and sharpen whatever handwriting their investigators might recover from the letters.
