Isolation and identification of male and female DNA on a postcoital condom

From crime scene to courtroom: A review of the current bioanalytical evidence workflows used in rape and sexual assault investigations in the United Kingdom

Sexual assault casework requires the collaboration of multiple agency staff to formalise an investigative pipeline running from crime scene to court. While the same could be said of many other forensic investigations, few require the additional support of health care staff and the combined forensic involvement of body-fluid examiners, DNA experts and analytical chemists. The sheer amount of collaborative effort between agencies is laid out through a detailed examination of the investigative workflow from crime scene to courtroom with each step in the pipelines detailed and discussed. Beginning with a review of sexual assault legislation in the United Kingdom this article details how sexual assault investigations are initiated by police and supported by sexual assault referral centre (SARC) staff who are often the first responders providing primary healthcare and patient support to victims while simultaneously collecting and assessing forensic evidence. Detailing the myriad of evidential material that can be documented and collected at the SARC, the review identifies and categorises key forensic tests to first detect and identify body-fluids recovered from evidence through to the secondary analysis of DNA to help identify the suspect. This review also focusses on the collection and analysis of biological material used to support the allegation that the sexual activity was non-consensual and provides a breakdown of common marks and trauma as well as a review of common analytical methods used to infer Drug Facilitated Sexual Assault (DFSA). The culmination of the investigative pipeline is discussed by reviewing the Rape and Serious Sexual Assault (RASSO) workflow used by the Crown Prosecution Service before providing our thoughts on the future of forensic analysis and possible changes to the described workflows.

Forensic Medical Examinations: Imagining Justice

Depending on the type of physical contact involved during a sexual assault offense, samples collected from a suspect's body may carry greater probative value than samples collected from a victim's body. However, unlike forensic medical examinations for persons identified as victims of a sexual assault, no professional consensus exists for what constitutes a high-quality forensic medical examination standard for persons identified as suspects, or the accused. The purpose of this article is to explore underlying assumptions that may contribute to disparate practices and inequalities in the provision of forensic medical examinations for persons suspected of committing a sexual offense and persons identified as victims of a sexual offense.

Forensic expertise and judicial practice: evidence or proof?

RATIONALE, AIMS AND OBJECTIVES

This study presents for discussion the possibility of adopting a hypothesis of absolute truth in forensic serology and DNA testing of biological traces, taking into account identification probability, which is usually assumed to be greater than 95%. Can this be so? Established identity and mathematically calculated probability below this rate is not false because it depends on the sensitivity of the method, the possible number of variations and theoretical combinations. The result from a study can be considered a 100% identification result only if this study takes account of absolutely all quantitative criteria that characterize it.

METHODS

Under the conditions of continually evolving theory and practice, and the introduction of modified and expanded methods for analysis of biological materials, it may therefore be asked which method considers 'everything'. Although this finding is nihilistic, it reflects a truth, which we can define as absolute. In forensic practice, research methods assumed to be orientation ones and others identified as evidence for the presence of biological traces on objects carriers, are routinely employed.

RESULTS

Based on several groups of forensic cases, the question of the limits of precision and relevance of the results to the categories of evidence and proof is formulated and discussed. Three groups of expertise cases are presented, which warrant discussion: (i) a study of condoms with genetic material on both sides: female DNA on the outer surface and male DNA on the inner. What is this evidence for or what does it prove?; (ii) a study of cigarette butts found at a crime scene with deposited cellular material from the offender. Is this evidence or proof?; (iii) the DNA expertise in the case of controversial parental origin or the vasectomy of the man referred to as the father.

CONCLUSIONS

What will the court choose as proof or is it a case of mutually exclusive evidence? Such considerations lead to the dilemma: 'evidence or proof'?

Direct analysis in real time mass spectrometry for analysis of sexual assault evidence

RATIONALE

Sexual assault crimes are vastly underreported and suffer from alarmingly low prosecution and conviction rates. The key scientific method to aid in prosecution of such cases is forensic DNA analysis, where biological evidence such as semen collected using a rape test kit is used to determine a suspect's DNA profile. However, the growing awareness by criminals of the importance of DNA in the prosecution of sexual assaults has resulted in increased condom use by assailants as a means to avoid leaving behind their DNA. Thus, other types of trace evidence are important to help corroborate victims' accounts, exonerate the innocent, link suspects to the crime, or confirm penetration.

METHODS

Direct Analysis in Real Time Mass Spectrometry (DART-MS) was employed for the comprehensive characterization of non-DNA trace evidence associated with sexual assault. The ambient ionization method associated with DART-MS is extremely rapid and samples are processed instantaneously, without the need for extraction, sample preparation, or other means that might compromise forensic evidence for future analyses.

RESULTS

In a single assay, we demonstrated the ability to identify lubricant formulations associated with sexual assault, such as the spermicide nonoxynol-9, compounds used in condom manufacture, and numerous other trace components as probative evidence. In addition, the method can also serve to identify compounds within trace biological residues, such as fatty acids commonly identified in latent fingerprints.

CONCLUSIONS

Characterization of lubricant residues as probative evidence serves to establish a connection between the victim and the perpetrator, and the availability of these details may lead to higher rates of prosecution and conviction, as well as more severe penalties. The methodology described here opens the way for the adoption of a comprehensive, rapid, and sensitive analysis for use in crime labs, while providing knowledge that can inform and guide criminal justice policy and practice.

The forensic nursing in sexual assaults: the immunochemical diagnosis and prevention of its adverse effects

Sexual assault was a ubiquitous and serious problem in our society. The world's care centers and forensic associations, which were at the forefront of scientific research in sexual assaults, discussed the role of the Forensic Nursing in their early diagnosis and their prevention, but little has been written in literature regarding their appropriate management. This article focuses on the immunochemical laboratory investigation in diagnosis and prevention of its adverse effects in sexual assaults and the role of the Forensic Nursing played in this task. After a careful reading of all the material received from many of the care centers and the associations contacted, a Forensic Nursing Examination Program, with specific immunochemical address, is identified.

DNA identification of biological traces and interpretation in a sexual assault case

The approaches in research and practical work in the forensic laboratories of DNA profiling in a sexual assault case can be assessed by the individual valuation of the quality and quantity of available DNA and the choice of combination of the STRs loci that have been examined. The applied procedures are classic or modificated extraction, amplification, and electrophoretical procedures, which have been selected for every individual case. We set up to present a criminal case of sexual assault over a woman, where the suspect used a condom which--after being examined--gave a negative sperm cytologic result. Our aim is to put some debatable issues and to propose an interpretation of the obtained results based on an association of the DNA typing of the victim and the suspect, separated only by the condom.

Suspension fluorescence in situ hybridization (S-FISH) combined with automatic detection and laser microdissection for STR profiling of male cells in male/female mixtures

Laser microdissection is a valuable tool for isolating specific cells from mixtures, such as male cells in a mixture with female cells, e.g., in cases of sexual assault. These cells can be stained with Y-chromosome-specific probes. We developed an automatic screening method to detect male cells after fluorescence in situ hybridization in suspension (S-FISH). To simulate forensic casework, the method was tested on female saliva after cataglottis (a kiss involving tongue-to-tongue contact) and on licking traces (swabs of dried male saliva on female skin) even after drying. After isolation of the detected cells, short tandem repeat profiling was performed. Full DNA profiles could consistently be obtained from as little as ten buccal cells. Isolation of five cells resulted in a mean of 98% (SD of 3.4%) of the alleles detected, showing that the developed S-FISH staining had no significant negative influence on DNA recovery and can be used in forensic casework.

The detection of female DNA from the penis in sexual assault cases

An investigation was performed with the aim of assessing the success rate of the examination of penile swabs or imprints for the detection of the female DNA profile. Two hundred twenty seven cases from a 3-year period were retrospectively reviewed. In 57% of the cases, no suitable material was available. Of the remaining 97 cases, 26 provided a DNA profile from the female victim. It is concluded that although the total success rate is low, it is worthwhile performing the examination, especially if there is a short interval between the alleged sexual assault and the examination.