Comparison of the elemental composition of office document paper: evidence in a homicide case
Spence, LD
Document Exam. Unit, Scientific Sect., Forensic and Technical Servs. Bra., Queensland Police Serv., GPO Box 1440, Brisbane Queensland, Australia.

Francis, RB
Trace Metals Grp., Inorganic Section, Queensland Health Scientific Servs., Queensland, Australia.

Tinggi, U
Organic Sect., Food Products (Trace Elements), Queensland Health Scientific Sers., Queensland, Australia.


Abstract
Fraudulent substitution of a page within a multiple page document such as a will or business contract, the counterfeit manufacture of paper banknotes, and linking ransom or extortion notes have all been the focus of criminal investigations at one time or another. In a recent homicide investigation, document examiners were requested to compare a threatening letter received by a business partner of the deceased with paper samples seized under warrant from a suspect's house. Through a quantitative elemental analysis of the concentrations of nine elements (Na, Mg, Al, Mn, Sr, Y, Ba, La, and Ce) within the questioned and specimen documents, determined by inductively coupled plasma-mass spectrometry (ICP-MS), it was concluded that (i) the paper of the threatening letter originated from a different source to that of the paper seized from the suspect's house and (ii) all six pages of paper seized from the suspect's house originated from the same source. This discrimination of paper is presented as both a statistical t-test analysis (99.9% confidence limit) as well as construction of an elemental fingerprint for individual replicates within the questioned and specimen sample populations. This is the first reported use of the comparison of the elemental composition of document paper, determined by ICP-MS, to assist in a criminal investigation.

Keywords:
document examination, document paper, elemental composition, elemental fingerprinting, elemental profile, elementary profile, fingerprints, forensic science, inductively coupled plasma spectroscopy, inductively coupled plasma-mass spectrometry

Paper ID: JFS4730648

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Author Spence LD, Francis RB, Tinggi U Title Comparison of the elemental composition of office document paper: evidence in a homicide case Symposium , Committee on