NIJ awards grant for tool to trace counterfeit bills

A US researcher has been awarded a US grant to develop chemical signatures that can be used to identify fake currency and documents.

Patrick Buzzini of Sam Houston State University received the National Institute of Justice (NIJ) grant to develop a technology that will allow illicit copies produced with colour inkjet printers to be traced back to the source. He is collaborating with the US Secret Service on the project.

"We are trying to develop a tool that can work at the investigative level," said Buzzini, an associate professor in the University's Department of Forensic Science. "Our hope is to produce chemical profiles that will be able to inform investigators about brands and models of printers used."

More than 60 per cent of counterfeit bank notes classified by the US Secret Service are made using inkjet printers because of their low cost and wide availability. Inkjet printers also may provide valuable evidence in questioned documents in such diverse cases as extortion, questioned contracts, identification documents, or anonymous letters.

In typical cases of counterfeit or questioned documents, a suspected document is compared to a reference sample using an optical inspection usually followed by thin layer chromatography to address questions about their source.

Buzzini's project is focusing on a different method - micro Raman spectroscopy - to determine to what extent suspected documents can be linked back to a source based on the three main colour components of the system, including mixes of cyan, magenta and yellow.

Spectroscopy methods - in this case used to detect dyes and pigments - study the interaction between light and materials. The Raman method measures the phenomenon of inelastic light scattering produced at the molecular level. In order to analyse fully this highly complex data, Buzzini will team up with James Curran of the University of Auckland in New Zealand to develop a novel statistical approach to analyse the results.

"He will help maximize the extraction of highly complex data," Buzzini said. The study will examine about 100 samples provided by the Criminal Investigation Division of the Treasury Obligation Section of the US Secret Service. The samples will be evaluated using both thin layer chromatography and Raman spectroscopy.

"Our goal is to investigate if Raman data gathered from three microscopic coloured spots of inkjet-printed document constitute, all together, a chemical signature sufficiently discriminating to provide reliable investigative leads in a time-effective and non-destructive manner," said Buzzini.