Forensic odontology lessons: multishooting incident at Port Arthur,Tasmania

On Sunday 28 April 1996 a lone gunman killed and injured many people at the historic penal settlement ruins at Port Arthur in South Eastern Tasmania, Australia. Thirty-two victims were shot dead and 19 were injured in a short time inside a cafe and along the roadway leading to the site entrance. The gunman then took one hostage to a nearby guest house which was occupied by a married couple. Police stood siege during the night. Early the next day the cottage began to burn and a man suspected to be the gunman eventually ran unarmed from the building with his clothes alight and was arrested. The house burned to the ground. Three bodies were later located in the burnt ruins. Forensic odontology played a role in the retrieval of evidence and identification of the incinerated victims. Lack of antemortem dental records for one victim necessitated the reliance on a single CT scan radiograph for matching with the remains. Fire scene procedures, evidence collection and other issues were reviewed. The overwhelming scale of this tragedy and its adverse effects on the Tasmanian community, especially the victims' families and survivors, cannot be overestimated. While acknowledging this, it is important that lessons are learnt from tragedies such as these. This paper is presented with a view to assisting forensic odontologists in the investigation of complex incidents.     

正常、大声两种说话状态下语音的声学差异及对声纹鉴定的影响

本文主要通过对正常、大声两种说话状态下的普通话中三个单元音[a]、[i]、[u]的声强、时长、基频、谐波振幅差值、共振峰等声学参数的分析,综合比较了各参数的变化规律,发现大声说话时的语音并非正常语音的简单放大,二者不仅在声强上存在差别,同时在频率域上也发生了重要变化。同一人不同状态下发音的频谱特征差异性较大,同种状态下发音的相似性、可比性较强,为此,声纹鉴定中应尽量选取状态相同的语音进行比对。     

正常、大声两种说话状态下语音的声学差异及对声纹鉴定的影响

本文主要通过对正常、大声两种说话状态下的普通话中三个单元音[a]、[i]、[u]的声强、时长、基频、谐波振幅差值、共振峰等声学参数的分析,综合比较了各参数的变化规律,发现大声说话时的语音并非正常语音的简单放大,二者不仅在声强上存在差别,同时在频率域上也发生了重要变化。同一人不同状态下发音的频谱特征差异性较大,同种状态下发音的相似性、可比性较强,为此,声纹鉴定中应尽量选取状态相同的语音进行比对。     

Questions,propositions and assessing different levels of evidence: Forensic voice comparison in practice

This paper contributes to the ongoing discussion about the distinction between observations and propositions in forensic inference, with a specific focus on forensic voice comparison casework conducted in the UK. We outline both linguistic and legal issues which make the evaluation of voice evidence and the refinement of propositions problematic in practice, and illustrate these using case examples. We will argue that group-level observations from the offender sample will always be evidential and that the value of this evidence must be determined by the expert. As such, a proposal is made that experts should, at least conceptually, think of voice evidence as having two levels, both with evidential value: group-level and individual-level. The two rely on different underlying assumptions, and the group-level observations can be used to inform the individual-level propositions. However, for the sake of interpretability, it is probably preferable to present only one combined conclusion to the end user. We also wish to reiterate points made in previous work: in providing conclusions, the forensic expert must acknowledge that the value of the evidence is dependent on a number of assumptions (propositions and background information) and these assumptions must be made clear and explicit to the user.