Despite significant ongoing research, a substantial proportion of latent fingermarks remain undet... more Despite significant ongoing research, a substantial proportion of latent fingermarks remain undetected in casework. Therefore, to improve existing detection techniques and to allow the development of new approaches, it is important to gain a better understanding of detection mechanisms rather than solely focusing on method formulations. As a starting point, it is crucial to gain a deeper understanding of the fingermark residue itself. Even if the chemical composition is reasonably well understood, little research has been reported on the physical aspects related to the deposition of fingermarks and their interactions with the environment and underlying substrates. This study aimed at exploring various techniques that can be used for the non-destructive visualisation of fingermarks before applying detection techniques. Both light and electron microscopy were investigated. Phase contrast imaging and environmental scanning electron microscopy, coupled with energy-dispersive X-ray spectrometry, proved to be essential tools for the study of latent fingermark deposits. These methods can be used to gather fundamental information that will add to our body of knowledge in this field.
Blowflies have relevance in areas of forensic science, agriculture, and medicine, primarily due t... more Blowflies have relevance in areas of forensic science, agriculture, and medicine, primarily due to the ability of their larvae to develop on flesh. While it is widely accepted that blowflies rely heavily on olfaction for identifying and locating hosts, there is limited research regarding the underlying molecular mechanisms. Using next generation sequencing (Illumina), this research examined the antennal transcriptome of Calliphora stygia (Fabricius) (Diptera: Calliphoridae) to identify members of the major chemosensory gene families necessary for olfaction. Representative proteins from all chemosensory gene families essential in insect olfaction were identified in the antennae of the blowfly C. stygia, including 50 odorant receptors, 22 ionotropic receptors, 21 gustatory receptors, 28 odorant binding proteins, 4 chemosensory proteins, and 3 sensory neuron membrane proteins. A total of 97 candidate cytochrome P450s and 39 esterases, some of which may act as odorant degrading enzymes,...
The aim of this project was to investigate the evidential value of blue and black ballpoint pen i... more The aim of this project was to investigate the evidential value of blue and black ballpoint pen inks in Australia. For this purpose, 49 blue and 42 black ballpoint pen inks, of different brands, models and batches, representative of those ballpoint pens available on the ...
Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning e... more Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) are compared in terms of their discrimination power when applied to Australian soil specimens. SEM/EDX and XRF are frequently used in forensic laboratories for the elemental analysis of paint and glass, and for miscellaneous examinations. LIBS is an emerging technique for forensic applications, with a number of researchers promoting its use for the elemental profiling of glass fragments. In this study, 29 soil specimens were analysed, with 12 specimens coming from the Canberra area and the remaining 17 specimens from other sites around Australia. As very good discrimination results were obtained for each of the analytical methods, any of these elemental analysis techniques, available in a trace evidence laboratory, could be used as part of a wider examination protocol to differentiate soil specimens.
Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning e... more Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) are compared in terms of their discrimination power when applied to Australian soil specimens. SEM/EDX and XRF are frequently used in forensic laboratories for the elemental analysis of paint and glass, and for miscellaneous examinations. LIBS is an emerging technique for forensic applications, with a number of researchers promoting its use for the elemental profiling of glass fragments. In this study, 29 soil specimens were analysed, with 12 specimens coming from the Canberra area and the remaining 17 specimens from other sites around Australia. As very good discrimination results were obtained for each of the analytical methods, any of these elemental analysis techniques, available in a trace evidence laboratory, could be used as part of a wider examination protocol to differentiate soil specimens.
An oil-in-water microemulsion containing a luminescent dye, nile red, has been synthesised using ... more An oil-in-water microemulsion containing a luminescent dye, nile red, has been synthesised using a solvent-diffusion method. This has been demonstrated to be effective in developing fresh latent fingermarks on porous surfaces. The working solution is made using a binary surfactant solution to create a lactescent dual organic-aqueous phase intermediate, which subsequently results in a transparent microemulsion after the organic solvent has evaporated. The solution is non-toxic and performs comparatively with a previously published methanolic formulation but at a much lower cost and with an extended shelf life. The microemulsion outperforms a previously reported aqueous nile blue formulation for the development of both charged and natural fresh fingermarks, and requires lower exposure times for image recording.
The 20th International Symposium on the Forensic Sciences (ANZFSS) was held in Sydney, Australia,... more The 20th International Symposium on the Forensic Sciences (ANZFSS) was held in Sydney, Australia, between September 5 and 9, 2010. The theme was ‘forensic science on trial’. Abstracts are provided here for all oral presentations given at the conference.
A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydri... more A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydride compound. The new dye was characterised by 1H NMR, UV-vis spectroscopy and fluorescence spectroscopy as well as quantum yield. The dye was absorbed onto titanium dioxide nanoparticles for use as a fingerprint detection powder. The new fluorescent powder was applied to latent fingermarks deposited onto different non-porous surfaces and compared with commercial fluorescent powders. The powder exhibits strong fluorescence at 650-700 nm under excitation at 505 nm. On glass surfaces, the new powder gave images showing tertiary-level detail of the fingermark ridges with almost no background development. Compared with current magnetic fluorescent powders, the new powder was slightly weaker in fluorescence intensity but produced significantly less background development, resulting in good contrast between the fingermark and the substrate.
A previously identified difficulty with the development of latent fingerprints on low-density pol... more A previously identified difficulty with the development of latent fingerprints on low-density polyethylene (LDPE) by vacuum metal deposition (VMD) is that excess gold deposition prevents effective zinc deposition and so inhibits latent print development [1]. The investigation of a means to correct for excess gold deposition was the basis for this study. Exposure to zinc and the readmission of air into the vacuum chamber followed by VMD development results in the deactivation of the initial gold clusters due to the formation of zinc oxide and the adsorption of air and water molecules. As a result, the majority of the gold deposited during the second treatment creates new gold clusters rather than adding to the gold clusters previously formed. After excess gold deposition on LDPE, the deposition of 1.5 times the optimum gold amount will result in good-quality normal development. The results also indicate that, on all surfaces, at least twice the initial gold count should be used for re-treatment when further development is required after air has been readmitted to the chamber.
The key role of a forensic scientist is to assist in determining whether a crime has been committ... more The key role of a forensic scientist is to assist in determining whether a crime has been committed, and if so, assist in the identification of the offender. Many people hold the belief that a particular item can be conclusively linked to a specific person, place or object. Unfortunately, this is often not achievable in forensic science. In performing their role, scientists develop and test hypotheses. The significance of those hypotheses that cannot be rejected upon completion of all available examinations/analyses is then evaluated. Although one can generally identify the substances present using available techniques, it is generally not possible to distinguish one source of the same substance from another. In such circumstances, although a particular hypothesis cannot be rejected, it cannot be conclusively proven, i.e. the samples could still have originated from different sources. This limitation of not being able to distinguish between sources currently extends to the analysis of other forensic samples including, but not limited to, ignitable liquids, paints, adhesives, textile fibres, plastics, and illicit drugs. Stable isotope ratio mass spectrometry (IRMS) is an additional technique that can be utilised to test a given hypothesis. This technique shows the potential to be able to individualise a range of materials of forensic interest. This paper provides a brief description of the technique, followed by a review of the various applications of IRMS in different scientific fields. The focus of this summary is on forensic applications of IRMS, in particular the analysis of explosives, ignitable liquids and illicit drugs.
Vacuum metal deposition (VMD) is an established technique for the development of latent fingerpri... more Vacuum metal deposition (VMD) is an established technique for the development of latent fingerprints on non-porous surfaces. VMD has advantages over cyanoacrylate fuming, especially in circumstances where prints are old, have been exposed to adverse environmental conditions, or are present on semi-porous surfaces. Under normal circumstances, VMD produces 'negative' prints as zinc deposits onto the background substrate and not the print ridges themselves. A phenomenon of 'reverse' development, when zinc deposits onto the print ridges and not the background, has been reported by many authors but its causes have not been conclusively identified. Four plastic substrates were used in this study and these could be easily divided into two groups based on the types of development observed as the amount of deposited gold was increased. On group I plastics, identified as low-density polyethylene (LDPE), normal development then reverse development and finally no development resulted with increasing gold. On group II plastics, identified as high-density polyethylene (HDPE), normal development then over-development and finally poor-quality normal development resulted with increasing gold. Our results suggest that the difference between these plastic types causes variations in the gold film structure which in turn dictates the nature of the zinc deposition. On group I plastics, the structure and thickness of the gold film has been identified as the critical factor in the occurrence of normal or reverse development. Thin gold films on plastic substrates form small 'clusters' (or agglomerates) rather than the atoms being uniformly spread over the surface. The size and shape of these clusters is critical. Once the clusters reach a certain morphology, they no longer act as nucleation sites for zinc, and hence, zinc will not deposit onto the substrate. On group II plastics, results suggest that the gold clusters are smaller and more densely packed. Hence, even though the same amount of gold has been deposited, the gold clusters in this case do not reach the critical morphology and so continue to act as nucleation sites for zinc.Typically, zinc will not deposit onto the fingerprint ridges as the gold nucleation sites are buried within the print residue. However, when more gold is deposited, gold emerges at the surface of the latent print allowing zinc deposition onto the ridges. The rate of gold evaporation was found not to affect the structure of the gold film, although a slower rate of evaporation resulted in more effective deposition.
Despite significant ongoing research, a substantial proportion of latent fingermarks remain undet... more Despite significant ongoing research, a substantial proportion of latent fingermarks remain undetected in casework. Therefore, to improve existing detection techniques and to allow the development of new approaches, it is important to gain a better understanding of detection mechanisms rather than solely focusing on method formulations. As a starting point, it is crucial to gain a deeper understanding of the fingermark residue itself. Even if the chemical composition is reasonably well understood, little research has been reported on the physical aspects related to the deposition of fingermarks and their interactions with the environment and underlying substrates. This study aimed at exploring various techniques that can be used for the non-destructive visualisation of fingermarks before applying detection techniques. Both light and electron microscopy were investigated. Phase contrast imaging and environmental scanning electron microscopy, coupled with energy-dispersive X-ray spectrometry, proved to be essential tools for the study of latent fingermark deposits. These methods can be used to gather fundamental information that will add to our body of knowledge in this field.
Blowflies have relevance in areas of forensic science, agriculture, and medicine, primarily due t... more Blowflies have relevance in areas of forensic science, agriculture, and medicine, primarily due to the ability of their larvae to develop on flesh. While it is widely accepted that blowflies rely heavily on olfaction for identifying and locating hosts, there is limited research regarding the underlying molecular mechanisms. Using next generation sequencing (Illumina), this research examined the antennal transcriptome of Calliphora stygia (Fabricius) (Diptera: Calliphoridae) to identify members of the major chemosensory gene families necessary for olfaction. Representative proteins from all chemosensory gene families essential in insect olfaction were identified in the antennae of the blowfly C. stygia, including 50 odorant receptors, 22 ionotropic receptors, 21 gustatory receptors, 28 odorant binding proteins, 4 chemosensory proteins, and 3 sensory neuron membrane proteins. A total of 97 candidate cytochrome P450s and 39 esterases, some of which may act as odorant degrading enzymes,...
The aim of this project was to investigate the evidential value of blue and black ballpoint pen i... more The aim of this project was to investigate the evidential value of blue and black ballpoint pen inks in Australia. For this purpose, 49 blue and 42 black ballpoint pen inks, of different brands, models and batches, representative of those ballpoint pens available on the ...
Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning e... more Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) are compared in terms of their discrimination power when applied to Australian soil specimens. SEM/EDX and XRF are frequently used in forensic laboratories for the elemental analysis of paint and glass, and for miscellaneous examinations. LIBS is an emerging technique for forensic applications, with a number of researchers promoting its use for the elemental profiling of glass fragments. In this study, 29 soil specimens were analysed, with 12 specimens coming from the Canberra area and the remaining 17 specimens from other sites around Australia. As very good discrimination results were obtained for each of the analytical methods, any of these elemental analysis techniques, available in a trace evidence laboratory, could be used as part of a wider examination protocol to differentiate soil specimens.
Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning e... more Laser-induced breakdown spectroscopy (LIBS), X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) are compared in terms of their discrimination power when applied to Australian soil specimens. SEM/EDX and XRF are frequently used in forensic laboratories for the elemental analysis of paint and glass, and for miscellaneous examinations. LIBS is an emerging technique for forensic applications, with a number of researchers promoting its use for the elemental profiling of glass fragments. In this study, 29 soil specimens were analysed, with 12 specimens coming from the Canberra area and the remaining 17 specimens from other sites around Australia. As very good discrimination results were obtained for each of the analytical methods, any of these elemental analysis techniques, available in a trace evidence laboratory, could be used as part of a wider examination protocol to differentiate soil specimens.
An oil-in-water microemulsion containing a luminescent dye, nile red, has been synthesised using ... more An oil-in-water microemulsion containing a luminescent dye, nile red, has been synthesised using a solvent-diffusion method. This has been demonstrated to be effective in developing fresh latent fingermarks on porous surfaces. The working solution is made using a binary surfactant solution to create a lactescent dual organic-aqueous phase intermediate, which subsequently results in a transparent microemulsion after the organic solvent has evaporated. The solution is non-toxic and performs comparatively with a previously published methanolic formulation but at a much lower cost and with an extended shelf life. The microemulsion outperforms a previously reported aqueous nile blue formulation for the development of both charged and natural fresh fingermarks, and requires lower exposure times for image recording.
The 20th International Symposium on the Forensic Sciences (ANZFSS) was held in Sydney, Australia,... more The 20th International Symposium on the Forensic Sciences (ANZFSS) was held in Sydney, Australia, between September 5 and 9, 2010. The theme was ‘forensic science on trial’. Abstracts are provided here for all oral presentations given at the conference.
A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydri... more A new, highly fluorescent dye was synthesised using oleylamine combined with a perylene dianhydride compound. The new dye was characterised by 1H NMR, UV-vis spectroscopy and fluorescence spectroscopy as well as quantum yield. The dye was absorbed onto titanium dioxide nanoparticles for use as a fingerprint detection powder. The new fluorescent powder was applied to latent fingermarks deposited onto different non-porous surfaces and compared with commercial fluorescent powders. The powder exhibits strong fluorescence at 650-700 nm under excitation at 505 nm. On glass surfaces, the new powder gave images showing tertiary-level detail of the fingermark ridges with almost no background development. Compared with current magnetic fluorescent powders, the new powder was slightly weaker in fluorescence intensity but produced significantly less background development, resulting in good contrast between the fingermark and the substrate.
A previously identified difficulty with the development of latent fingerprints on low-density pol... more A previously identified difficulty with the development of latent fingerprints on low-density polyethylene (LDPE) by vacuum metal deposition (VMD) is that excess gold deposition prevents effective zinc deposition and so inhibits latent print development [1]. The investigation of a means to correct for excess gold deposition was the basis for this study. Exposure to zinc and the readmission of air into the vacuum chamber followed by VMD development results in the deactivation of the initial gold clusters due to the formation of zinc oxide and the adsorption of air and water molecules. As a result, the majority of the gold deposited during the second treatment creates new gold clusters rather than adding to the gold clusters previously formed. After excess gold deposition on LDPE, the deposition of 1.5 times the optimum gold amount will result in good-quality normal development. The results also indicate that, on all surfaces, at least twice the initial gold count should be used for re-treatment when further development is required after air has been readmitted to the chamber.
The key role of a forensic scientist is to assist in determining whether a crime has been committ... more The key role of a forensic scientist is to assist in determining whether a crime has been committed, and if so, assist in the identification of the offender. Many people hold the belief that a particular item can be conclusively linked to a specific person, place or object. Unfortunately, this is often not achievable in forensic science. In performing their role, scientists develop and test hypotheses. The significance of those hypotheses that cannot be rejected upon completion of all available examinations/analyses is then evaluated. Although one can generally identify the substances present using available techniques, it is generally not possible to distinguish one source of the same substance from another. In such circumstances, although a particular hypothesis cannot be rejected, it cannot be conclusively proven, i.e. the samples could still have originated from different sources. This limitation of not being able to distinguish between sources currently extends to the analysis of other forensic samples including, but not limited to, ignitable liquids, paints, adhesives, textile fibres, plastics, and illicit drugs. Stable isotope ratio mass spectrometry (IRMS) is an additional technique that can be utilised to test a given hypothesis. This technique shows the potential to be able to individualise a range of materials of forensic interest. This paper provides a brief description of the technique, followed by a review of the various applications of IRMS in different scientific fields. The focus of this summary is on forensic applications of IRMS, in particular the analysis of explosives, ignitable liquids and illicit drugs.
Vacuum metal deposition (VMD) is an established technique for the development of latent fingerpri... more Vacuum metal deposition (VMD) is an established technique for the development of latent fingerprints on non-porous surfaces. VMD has advantages over cyanoacrylate fuming, especially in circumstances where prints are old, have been exposed to adverse environmental conditions, or are present on semi-porous surfaces. Under normal circumstances, VMD produces 'negative' prints as zinc deposits onto the background substrate and not the print ridges themselves. A phenomenon of 'reverse' development, when zinc deposits onto the print ridges and not the background, has been reported by many authors but its causes have not been conclusively identified. Four plastic substrates were used in this study and these could be easily divided into two groups based on the types of development observed as the amount of deposited gold was increased. On group I plastics, identified as low-density polyethylene (LDPE), normal development then reverse development and finally no development resulted with increasing gold. On group II plastics, identified as high-density polyethylene (HDPE), normal development then over-development and finally poor-quality normal development resulted with increasing gold. Our results suggest that the difference between these plastic types causes variations in the gold film structure which in turn dictates the nature of the zinc deposition. On group I plastics, the structure and thickness of the gold film has been identified as the critical factor in the occurrence of normal or reverse development. Thin gold films on plastic substrates form small 'clusters' (or agglomerates) rather than the atoms being uniformly spread over the surface. The size and shape of these clusters is critical. Once the clusters reach a certain morphology, they no longer act as nucleation sites for zinc, and hence, zinc will not deposit onto the substrate. On group II plastics, results suggest that the gold clusters are smaller and more densely packed. Hence, even though the same amount of gold has been deposited, the gold clusters in this case do not reach the critical morphology and so continue to act as nucleation sites for zinc.Typically, zinc will not deposit onto the fingerprint ridges as the gold nucleation sites are buried within the print residue. However, when more gold is deposited, gold emerges at the surface of the latent print allowing zinc deposition onto the ridges. The rate of gold evaporation was found not to affect the structure of the gold film, although a slower rate of evaporation resulted in more effective deposition.
Uploads
Papers