Cold Case Homicides: DNA Testing of Retained Autopsy Sexual Assault Smears

Archival medical examiner specimens may contain perpetrator DNA evidence useful in unsolved (“cold case”) homicides. The Office of the Chief Medical Examiner (OCME) histology slide archives were searched for sexual assault smears for all 376 female homicides from 1990 to 1999. Of these, the OCME had sexual assault smears on 84 of which 13 slides had sperm. Of these 13, six were still unsolved. DNA profiles were obtained on all six (5 from smears and one from swabs). Combined DNA Index System ( submission resulted in two matches (“hits”) for new suspects. In addition, three suspects were eliminated in two cases. Our review of archival sexual assault smears resulted in DNA profiles that were able to assist in the investigation of four cold case homicide investigations. It may be worthwhile for medical examiner offices to search their archival histology slides for sexual assault smears on previously unsolved cases particularly those prior to the mid‐1990s when DNA testing was less widely available.     

Forensic approach to analyzing rape cases

With large number of criminal acts, such as rape and murder, identification of the perpetrator is very difficult to determine. The cause is the lack of sufficient quantity of biological traces provided as material evidence, or the biological material is decomposed and no result can be obtained by using other identification methods. Thus the case remains unsolved. The purpose of this research is to establish a reliable method for detecting semen presence in rape cases and to get DNA profile from the perpetrator of a crime. Vaginal swabs were taken using cotton swabs during gynecological examination or autopsy in 21 cases. The chemical detection of semen presence was performed using Phospathesmo Kits. The DNA extraction was performed using QIAAamp^® DNA Mini Kit. The amplification was performed using AmpFistrIdentifiler Kit and AmpFistrYfiler Kit. The electrophoresis was performed using 310 ABI squenator. Results indicate that DNA profile was obtained in 4 cases where chemical tests did not prove semen presence using Phospathesmo Kits. In one case, neither semen presence was chemically proven nor DNA profile was obtained for autosomal STRs, but a profile for Y-STRs was obtained. Our analyses indicate that when the victim's body is examined within the first few hours or the first day, a genetic profile of the perpetrator of the criminal act is obtained. Besides using autosomal STRs, we recommend Y-STRs to be used in all rape cases, too, thus separating the male from female profile, and also the male kinship relatedness in cases of incest could be followed, the rape performed by several blood-related men or similar.     

A study of the potential risk of gunshot residue transfer from special units of the police to arrested suspects

The presence of gunshot residues (GSRs) on arrested suspects can help the Court to form an opinion regarding the possibility of utilization of firearms by these suspects. Since the presence of a few particles can in some cases already have a strong indicative value, the GSR experts have to evaluate in their daily work the risk of a potential contamination of these suspects during their arrest. A few studies conducted on police officers and police facilities concluded that the risk of secondary transfer on arrested suspects is quite negligible. However, the case of special force units of the police should be taken into account, since these units can be assumed to be highly contaminated by GSR due to their intensive training. The aim of this study is to evaluate this possibility of particle transfer by performing simulations of arrests by special force police units, according to both low and high contamination scenarios. The results show that secondary transfers of GSR during these simulations are in most cases not negligible, even for the low contamination scenario. This is especially apparent on the vests of the target persons, with an average of 7 GSR particles (2 PbBaSb and 5 TiZn) found on the stubs used on these materials. Of course, the major contamination levels were observed in the case of the high contamination scenario, due to the use of highly contaminated gloves by the police officers during the arrests. Some recommendations are proposed to take into account this risk of contamination and to try to minimize it, or at least to better identify it.     

Analysis of salivary DNA evidence from a bite mark on a body submerged in water.

A female body was recovered after approximately 5.5 h in a river with slow-moving current. On the victim's right breast, a patterned injury was discovered and determined to be from human adult teeth. Evidence was collected according to established techniques including recovery of saliva from the bite mark area despite the body being found submerged in water. DNA analysis by PCR using polymorphic STR markers revealed a DNA profile of mixed origin. In addition to the victim's DNA profile, a genotype contribution from the perpetrator was identified as a minor component. The DNA typing results from the bite mark correlated with the DNA typing results obtained from other biological trace evidence identified from the victim's genital samples. The bite mark and the DNA evidence were used to screen suspects and played an important role in obtaining resolution of this case. Consequently, it is advisable that investigators routinely swab for salivary DNA in bite mark cases, even when the amount is thought to be minimal.     

诉讼法视野中的法医DNA证据研究

作为一种科学证据,法医DNA证据在凶杀、性犯罪等案件的审判中被广泛运用。但是该证据能否最终被法庭采纳,取决于其提取、保管、送检以及鉴定过程中是否受到一系列严格的诉讼程序加以规范,并经过庭审的质证,从而最终通过法庭的审查判断。而庭审质证能否有效进行,又与警察、鉴定人出庭作证以及交叉询问制度的真正确立息息相关。     

Cross‐Cultural Comparison of Two Serial Sexual Murder Series in Italy and the United States

Abstract: There have been few documented comparisons of serial murder cases committed in the United States with cases occurring internationally. The authors contrasted two unique serial murder series: one in Italy and one in the United States by examining the details of both series, including the M.O., motivation, crime scene interactions, sexual acts performed, and the general backgrounds of both offenders. The comparison revealed a number of similarities. Both offenders specifically targeted elderly women, who were attacked in their residences. The two series involved sexually motivated crimes, although the sexual interactions were different. Both offenders stole objects from their victims after the murders and each kept newspaper accounts of their crimes. In addition, both offenders claimed to have abusive upbringings, including sexual abuse.     

Experiences with single locus DNA probes in casework.

DNA profiling in this laboratory has been employed primarily in cases of sexual assault and the largest category of items examined has been internal vaginal swabs. 79% of these gave a profile which was different from that of the victim. Results have been obtained from swabs taken up to 70 h after intercourse. In cases where DNA results were obtained, one or more suspects were excluded in 29% of the cases.     

The effect of NucleoSpin® Forensic Filters on DNA recovery from trace DNA swabs

Forensic DNA profiling is a globally accepted method for human identification, however, obtaining full DNA profiles from trace DNA can be challenging. The optimal recovery of DNA from trace DNA swabs is therefore crucial. Methods for extracting DNA from swabs often make use of a spin basket combined with a centrifugation step, to enhance the release of cells from the swab prior to DNA extraction. The NucleoSpin® Forensic Filter (Macherey-Nagel, Düren) is a type of spin basket, but it has not been thoroughly assessed on trace DNA samples. This study aimed to assess if the inclusion of the NucleoSpin® Forensic Filter significantly improved DNA recovery and DNA profiling success from cotton and flocked swabs used to collect trace DNA and buccal cells (control). Buccal cells and trace DNA samples were collected from 25 volunteers using each swab type (cotton and flocked) in duplicate. DNA was extracted from the samples using the NucleoSpin® DNA Forensic kit, one set with, and the other set without, NucleoSpin® Forensic Filters. DNA concentration was assessed using real time PCR, and DNA profiling was done using the PowerPlex® ESX 16 system. The inclusion of the NucleoSpin® Forensic Filters significantly improved DNA concentration for buccal cells that were collected using flocked swabs (p = 0.035). However, no significant differences were noted for trace DNA samples for either swab type. There was also no significant difference in DNA profiling success when NucleoSpin® Forensic Filters were used, regardless of swab and sample type. These results may be helpful for laboratories that are considering the NucleoSpin® Forensic Filters in the DNA extraction workflow, particularly for trace DNA samples.     

Quality assurance testing of an explosives trace analysis laboratory--further improvements

The Forensic Explosives Laboratory (FEL) operates within the Defence Science and Technology Laboratory (DSTL) which is part of the UK Government Ministry of Defence (MOD). The FEL provides support and advice to the Home Office and UK police forces on matters relating to the criminal misuse of explosives. During 1989 the FEL established a weekly quality assurance testing regime in its explosives trace analysis laboratory. The purpose of the regime is to prevent the accumulation of explosives traces within the laboratory at levels that could, if other precautions failed, result in the contamination of samples and controls. Designated areas within the laboratory are swabbed using cotton wool swabs moistened with ethanol water mixture, in equal amounts. The swabs are then extracted, cleaned up and analyzed using Gas Chromatographs with Thermal Energy Analyzer detectors. This paper follows on from a previous published paper describing the regime and summarizing subsequent results from approximately 6 years of tests. Lessons learned and improvements made over the period are also discussed. Monitoring samples taken from surfaces within the trace laboratories and trace vehicle examination bay have, with few exceptions, revealed only low levels of contamination, predominantly of RDX. Analysis of the control swabs, processed alongside the monitoring swabs, has demonstrated that in this environment the risk of forensic sample contamination, assuming all the relevant anti-contamination procedures have been followed, is so small that it is considered to be negligible. The monitoring regime has also been valuable in assessing the process of continuous improvement, allowing sources of contamination transfer into the trace areas to be identified and eliminated.     

Japanese Suspect Interviews,Confessions, and Related Factors

Two hundred and ninety-one new adult male inmates convicted of murder, robbery, arson, rape, forcible indecency, and kidnapping completed questionnaires about their pretrial interviews. Logistic regression analyses revealed that marital status, feelings of guilt, and perceptions of the strength of the evidence significantly affected the likelihood of confession by those who had already decided to confess prior to interview. By contrast, prior arrest history and interview style affected the likelihood of confession by those who had not previously decided to confess. Suspects who had no previous arrests and had undergone either Undifferentiated-high or Relationship-focused interviews were more likely to make full confessions. In Undifferentiated-high interviews, police officers employed all of the interviewing techniques examined: they listened closely to the suspects’ accounts, attempted to build good relationships, and discussed the crimes, while also presenting evidence and confronting the suspects. In Relationship-focused interviews, police officers listened attentively to the offenders’ accounts, tried to build good relationships, and discussed the crimes directly. Prisoners who experienced Relationship-focused interviews felt satisfied with their confessions and admitted guilt at trial.     

诉讼法视野中的法医DNA证据研究

作为一种科学证据,法医DNA证据在凶杀、性犯罪等案件的审判中被广泛运用。但是该证据能否最终被法庭采纳,取决于其提取、保管、送检以及鉴定过程中是否受到一系列严格的诉讼程序加以规范,并经过庭审的质证,从而最终通过法庭的审查判断。而庭审质证能否有效进行,又与警察、鉴定人出庭作证以及交叉询问制度的真正确立息息相关。     

Evaluation of the use of freezer mill to improve DNA retrieval from dried cotton swabs

This investigation evaluated the use of a freezer mill to improve retrieval of DNA from dried cotton swabs (using 100 μl saliva) compared to uncrushed swabs and whole saliva by measuring DNA yield and profile average peak height. Three treatments were tested; short, medium (as for a bone sample) and extended. The samples subjected to the freezer mill had the powder that remained on the freezer mill components collected (using a water and agitation method). All freezer mill samples returned a lower average DNA yield than either uncrushed swabs or whole saliva. The powder from the crushed swabs comprised an average of 35% of the total DNA yield, whereas the powder from the components comprised 65%. Allele drop-out was observed in samples exposed to extended treatments. Both short and medium treatments provided significantly higher peak heights than uncrushed cotton swabs with equal quantities of DNA (P < 0.05). Using a freezer mill on dried cotton swabs does not increase the DNA yield. This investigation suggests collecting powder from the freezer mill components will increase DNA yield, especially from trace samples.     

香港特别行政区的DNA数据库

香港特区的DNA数据库成立于2001年,法例上此数据库直属于香港警务处长,由香港政府化验师代行管理及维护。被定罪人士其罪行最高刑期为监禁7年或以上及任何罪案之疑犯均可被套取其口腔拭子样本,利用美国App lied B iosystem s的试剂进行DNA分型测试。所确立之DNA图谱将上载到由美国FB I(联邦调查局)在2000年免费为香港政府化验所提供的,名为COD IS(Comb ined DNA Index System)的计算机系统;在罪案现场所收集到的不明来历的DNA数据样本亦会被上载到COD IS。被定罪人士及疑犯的DNA图谱会定期与罪案现场的DNA数据在CO-D IS内进行较对以便协助警方调查。本文介绍香港DNA数据库的操作,其中包括统计数据的讨论。     

论毒品犯罪案件的证据

毒品犯罪案件有许多不同于普通刑事案件的特殊性,毒品案件中的证据又具有相对的单一性,必须当场缴获毒品和毒资才能证实犯罪。本文结合缉毒侦查中的具体情况,强调办理毒品案件必须增强证据意识,要把握好破案的时机,适时取证;收集证据一定要十分仔细,获取的证据应做好固定保全工作,并特别注意取证的合法性;采用技术侦察手段须把握住一条底线:不得诱人犯罪;应正确运用推定规则判定"明知",对推定结论允许以确凿的事实予以反驳。     

Applicability of DNA analysis on adhesive tape in forensic casework

Adhesive tape is commonly used in crimes and is often the subject of forensic evaluation. DNA analysis of adhesive tape can provide DNA profiles of suspects. The object of this study was to evaluate the applicability of DNA analysis on adhesive tape samples in forensic casework. We retrospectively reviewed all cases involving adhesive tape or similar items received by our institute for DNA analysis during the past 11 years. From 100 forensic cases reviewed, 150 adhesive tape samples were examined. A total of 98 DNA profiles were obtained from these samples. Sixty-two of the profiles provided feasible case-relevant information. In conclusion, DNA profiling of adhesive tape samples can be useful in a variety of forensic cases.     

Melodramatic and consentient images in introductory criminal justice textbooks

Previous scholarly attention to introductory criminal justice textbooks observed the texts' organization, structure, and content. This study added to this literature by examining the photographs used in ten leading criminal justice textbooks when providing demographic portraits (e.g., race, gender) of alleged and convicted criminals, criminal offenses, clothing and appearances (of suspects/criminals), and the degree to which authorities confined suspects/criminals. In regard to the above, this study distinguished between consentient (relying on systematic empirical findings) and melodramatic (relying on more sensationalized news coverage) images and representative (quantitatively standard) and notorious (qualitatively distinct) crimes. Results suggested texts provided consentient images of suspect/offender race and gender, but relied on melodramatic images in disproportionate depictions of suspects/defendants charged with, or convicted of murder. Further, it was found that although notorious crimes and criminals represent qualitative rarities in the overall criminal justice system, they were depicted in 31 percent of images presented in texts.     

Surface-sampling and analysis of TATP by swabbing and gas chromatography/mass spectrometry

The method of sample recovery for trace detection and identification of explosives plays a critical role in several criminal investigations. After bombing, there can be difficulties in sending big objects to a laboratory for analysis. Traces can also be searched for on large surfaces, on hands of suspects or on surfaces where the explosive was placed during preparatory phases (e.g. places where an IED was assembled, vehicles used for transportation, etc.).In this work, triacetone triperoxide (TATP) was synthesized from commercial precursors following reported methods. Several portions of about 6 mg of TATP were then spread on different surfaces (e.g. floors, tables, etc.) or used in handling tests. Three different swabbing systems were used: a commercial swab, pre-wetted with propan-2-ol (isopropanol) and water (7:3), dry paper swabs, and cotton swabs wetted with propan-2-ol. Paper and commercial swabs were also used to sample a metal plate, where a small charge of about 4 g of TATP was detonated. Swabs were sealed in small glass jars with screw caps and Parafilm^® M and sent to the laboratory for analysis. Swabs were extracted and analysed several weeks later by gas chromatography/mass spectrometry. All the three systems gave positive results, but wetted swabs collected higher amounts of TATP. The developed procedure showed its suitability for use in real cases, allowing TATP detection in several simulations, including a situation in which people wash their hands after handling the explosive.     

Quality assurance testing of an explosives trace analysis laboratory — Further improvements to include peroxide explosives

The Forensic Explosives Laboratory (FEL) operates within the Defence Science and Technology Laboratory (DSTL) which is part of the UK Government Ministry of Defence (MOD). The FEL provides support and advice to the Home Office and UK police forces on matters relating to the criminal misuse of explosives. During 1989 the FEL established a weekly quality assurance testing regime in its explosives trace analysis laboratory. The purpose of the regime is to prevent the accumulation of explosives traces within the laboratory at levels that could, if other precautions failed, result in the contamination of samples and controls. Designated areas within the laboratory are swabbed using cotton wool swabs moistened with ethanol:water mixture, in equal amounts. The swabs are then extracted, cleaned up and analysed using Gas Chromatography with Thermal Energy Analyser detectors or Liquid Chromatography with triple quadrupole Mass Spectrometry. This paper follows on from two previous published papers which described the regime and summarised results from approximately 14 years of tests. This paper presents results from the subsequent 7 years setting them within the context of previous results. It also discusses further improvements made to the systems and procedures and the inclusion of quality assurance sampling for the peroxide explosives TATP and HMTD. Monitoring samples taken from surfaces within the trace laboratories and trace vehicle examination bay have, with few exceptions, revealed only low levels of contamination, predominantly of RDX. Analysis of the control swabs, processed alongside the monitoring swabs, has demonstrated that in this environment the risk of forensic sample contamination, assuming all the relevant anti-contamination procedures have been followed, is so small that it is considered to be negligible. The monitoring regime has also been valuable in assessing the process of continuous improvement, allowing sources of contamination transfer into the trace areas to be identified and eliminated.     

常州市武进区5年94例已破命案的回顾性研究

目的本课题收集真实案例进行回顾性研究、比对,寻找常州市武进区命案特征,总结命案现场的法医学检案重点、难点和相关实践经验。方法收集江苏省常州市武进区2006～2010年94例已破命案资料,应用Microsoft Excel软件进行一般描述性统计分析。结果 2009年、2010年案件数量略有上升,而每年的第一、三季度为命案高发季度。受害人及嫌疑人多为流动人口,男性显著多于女性,以青壮年为主。嫌疑人均学历较低,多从事打工、务农,或无业,多由纠纷升级为命案。以锐器伤及钝器伤多见,死因基本为机械性损伤和机械性窒息。结论命案发生与人口数量呈正相关。受害人及犯罪嫌疑人基本情况、作案动机、致伤工具、损伤分布、死因等均反映出了命案现场法医工作的基本内容、工作重要性及未来的研究发展方向。     

DNA typing of forensic material with mixed genotypes using allele-specific enzymatic amplification (polymerase chain reaction).

Biological material in forensic casework frequently contains a mixture of genotypes, with a predominance of material from the victim and only trace amounts from the person committing the crime. Physical separation of the two genotypes or preferential lysis of different cell types may sometimes be possible. However, it is often difficult to achieve complete separation due to the lysis of cells or lack of material. We have developed an enzymatic amplification system for the HLA DQA1 locus, that will allow the presence of individual alleles in a sample with mixed genotypes to be determined, independent of their initial proportion in the sample. This system permits the identification of an allele representing less than 10(-4) of the background genotype. Use of polymerase chain reaction (PCR) with general primers allows only alleles representing more than about 1% to be detected, while the allele-specific amplification represents up to a 1000-fold increase in sensitivity. This method was applied to a rape case and a combined rape and murder case; in both cases the biological evidential materials contained a mixture of alleles from the victim and the rapist. Allele-specific PCR revealed the presence of alleles identical to those of the suspect using DNA from a vaginal swab taken after a rape incident, whereas by using general primers in the PCR only trace amounts of alleles other than those of the victim were found. Similarly, allele-specific amplification of DNA from vaginal swabs from the murder case revealed the presence of alleles identical to those of the suspect, while standard PCR only indicated the presence of genetic material from the victim.