Lee L.K*, Michael Tay Ming Kiong
International Association of Forensic Sciences, 16th Triennial Meeting
August 2002, Montpellier, France. (poster presentation)
Objectives: This paper surveys the different types of materials used by pranksters in anthrax hoaxes in Singapore after the September 11 terrorist attacks on the World Trade Center.
Nature of study: Following the September 11 incident, more than 25 pranksters in Singapore and abroad tried to create anthrax scares in Singapore by sending anonymous letters and packages containing white substances, often with threatening messages, or by sprinkling white powders in private and work areas. This string of hoaxes in Singapore began in early October, soon after anthrax-related incidents struck the United States. Most anthrax hoax letters were sent via normal mail service to various government and private buildings. After microbiological screening revealed the absence of anthrax bacteria and spores, these white powders and stained articles were chemically examined to identify the white substances used. Under Singapore law, those who make anonymous threats to cause death or serious harm can be jailed for up to nine years.
Materials and methods: This study was based on materials submitted to our laboratory as physical evidence in some 17 anthrax hoax cases in Singapore. Methods of analyses include stereomicroscopy, scanning electron microscopy with energy-dispersive X-ray analysis (SEM/EDX), polarised light microscopy (PLM), Fourier-Transform infrared microspectrophotometry (FT-IR) and gas chromatography with mass spectrometry (GC/MS).
Results: Both organic and inorganic powders were used by pranksters. Some of the hoax samples and white powder stains were compared with white powders seized from the homes or possessions of pranksters. Powders used include talcum powders, fine sugar, flours and other whitish materials. Talcum powders were most frequently used by pranksters. Apochromatic stereomicroscopy and SEM/EDX were useful in revealing the morphology and size of the fine particles. Talcum powder was easily identified using SEM/EDX. Large organic molecules were identified by FT-IR microscopy and confirmed using polarised light microscopy (PLM). PLM was useful for differentiating between different starches and flours (potato, tapioca, corn, rice, wheat). GC/MS was used to analyse fragrances present in some talcum powders. This paper will present both analytical results and a statistical study on the different substances used by anthrax hoaxers in Singapore.
Conclusion: White powders used in anthrax hoaxes in Singapore were identified and our study indicated the types of materials commonly used in such pranks.