Some Forensic Aspects on Drug-Facilitated Sexual Assault

The determination of the time since the deposition of a biological stain can be crucial to many forensic cases. It may establish a timeframe for when a crime occurred and exclude potential suspects from an investigation. This timestamp becomes especially significant in crimes in which the victim and the suspect are known to one another. Moreover, such estimations can often be used to substantiate other comparable evidence, for instance, witness statements, a suspect’s physical presence, etc.

Although many techniques have been used to determine the age of biological stains, none so far has been developed to a level whereby it can be reliably used in casework. Most research has been conducted on bloodstains, primarily because of their frequent presence [1,2]. These techniques include simple tests that depend on visual observations, as well as those that use sophisticated equipment, such as GC-MS, High-Performance Liquid Chromatography (HPLC) and Electron Paramagnetic Resonance (EPR) spectroscopy [1,3-14]. However, there are many limitations associated with these techniques in terms of precision, accuracy and sample size.

The in vitro instability and lability of RNA drew attention to using it to estimate the time since the deposition of a biological stain. Many studies have been carried out to assess RNA for this purpose. Several published articles have considered the application of RNA to determine blood stain age, with exceptionally promising results [15-17], and have demonstrated the correlation between the age of blood stains and RNA degradation. Anderson et al. [17] have found a statistically significant correlation between the relative quantity ratio (RQR) of β-actin mRNA to 18S rRNA and the time since deposition, or age, of blood stains [16]. The change in the measured RQR of the sample as it aged was attributed to the difference in the degradation rate of the two RNA species, with 18S rRNA being less prone to degradation than β-actin mRNA. It was claimed that this approach offered a number of potential advantages over the previous spectroscopic and chromatographic based techniques. Additionally, this approach could be applied to tissue types other than blood because the RNA species are chosen from genes that are universally expressed. The analysis is not affected by the size of the sample because it examines the RNA ratio [16]. Indeed, Hampton et al. [18] successfully applied this approach to hair samples to determine their age over a period of three months.

However, the markers used in this method are housekeeping RNAs, which are expressed in all tissues at varying levels [19-22]. This may result in changing the RQR value of tested stains in cases in which they have been mixed with other body fluids. This may in turn affect the age estimation of such stains. For example, a mixture of blood with saliva is indistinguishable from only blood because of the consistency of saliva. As the mixture of body fluids, either from one or more people is commonly observed in forensic practice, the aim of this study is to evaluate the effect of blood-saliva mixture on the RQR value of bloodstains and their estimated ages. Four types of mixtures of blood with saliva are considered in this study: fresh blood with fresh saliva, fresh blood with aged saliva, aged blood with fresh saliva and aged blood with aged saliva. Each of these mixtures will be studied as a case. The RQR values were calculated from the ratio of β-actin mRNA over 18S rRNA as suggested by Alrowaithi et al. [23].

Samples

Stains of blood, saliva and a mixture of both were made on clean cotton swabs.

Firstly, pure blood and pure saliva stains were prepared as follows:

Stains made from one type of body fluid, or ‘pure’ stains were prepared from blood and saliva collected from five volunteers, with informed consent, via standard venepuncture for blood and spitting for saliva. From each volunteer, two pure stains for blood (20μL) and two for saliva (50μL) were made on clean cotton swabs to create ten stained swabs of each type of body fluid. Each stain was allowed to dry at room temperature in natural light inside a sterile hood and was then extracted as a dry, fresh, pure stain.

In addition, from blood and saliva collected from four volunteers, eight more pure stains were prepared for each type of body fluid sample from the same volunteers. These additional stains were kept for specific “ages” (i.e., two stains for 10 days, two stains for 30 days and four stains for nine months) before the preparation of mixed stains by the addition of fresh blood or saliva, as described below.

Secondly, four types of mixture stains from the volunteers were prepared from the blood and saliva that had been collected when the stains of pure body fluids were prepared.

The mixture stains consisted of:

1. Fresh blood and fresh saliva were prepared by adding 50μL of fresh saliva to 20μL of fresh aliquoted blood on cotton swabs. These were extracted after drying.

2. Fresh blood and aged saliva were prepared by adding 20μL of fresh blood to previously prepared aged saliva stains.

3. Aged blood and fresh saliva were prepared by adding 50μL of fresh saliva to previously prepared aged bloodstains.

4. Aged stains of blood and saliva were prepared by mixing fresh blood and saliva and stored to reach various ages, as specified above, and left in a dry place until they reached specific ex vivo ages prior to extraction.

All types of mixtures of blood and saliva are shown in Table 1.

Each of the following mixture combinations was prepared in duplicate, using blood and saliva from five volunteers for Mixture type 1. Other mixture types were prepared using samples from four volunteers giving 34 mixture stains in all. Figure 1 shows the timeline of collection and preparation of stains prior to extraction.

Law enforcement agencies must be aware of the signs of a drugfacilitated sexual assault so that they can properly document and collect physical evidences and help the victim to decide if a “full drug screen” is necessary. This is particularly essential in cases where GHB, Flunitrazepam, Ketamine and other “date rape drugs” may have been surreptitiously given to the victim. The first responding officer should secure and collect urine sample for toxicological testing if it is suspected that a drug was ingested within 96 hours. If the drug was ingested within 12 hours, the victim should also be transported to the nearest medical facility to obtain a blood sample.

The investigator must carefully deduce from the types of drugs used to facilitate the sexual assault, the effects these drugs had on the victim, and an account of the events surrounding the actions of everyone involved. The crime scene investigator may be the first to suspect the victim was drugged to facilitate a sexual assault from the victim’s urine and blood screened as soon as possible for traces of Flunitrazepam and their metabolites, GHB, Ketamine and any other possible drugs. Vomit should be collected in addition to the urine and blood specimens. To assist the toxicologist, the investigating officer should be diligent in properly documenting their case. During investigation note what drugs-voluntarily or involuntarily were ingested in the last five days-that might have incapacitated or contributed to the incapacitation/vulnerability of the victim. Keep in mind that in a drug-facilitated rape case, more than one drug may have contributed to the incapacitation/vulnerability of the victim. Evidences before submitted for conducting a “Full Drug Screen,” in forensic toxicology laboratory it should be confirmed that the laboratory is testing the urine and blood samples for: Benzodiazepines, Amphetamines, Muscle relaxants, Cocaine, Marijuana, Barbiturates, Opiates, Antihistamines, Ethanol, Sleep aids and any other substance that depresses the central nervous system.

The crime scene related to a drug-facilitated sexual assault may contain physical evidences like packages of Flunitrazepam and other drugs, Empty bubble packages and other material in which drugs could be packaged, precursors/reagents, prescriptions paper of sleeping aids, muscle relaxants, and sedatives, liquor bottles, mixers, punch bowls-look for drug residue, containers for GHB, glasses, soda cans and bottles any containers for any residue of drugs, possible vomit from the victim-may be a source of drug residue, video/camera equipment, videotapes, photographs, and compact disk of sexual assault victim, pornographic literature containing suggestions of drugging women to facilitate sexual assault, Internet information/pamphlets on Flunitrazepam and GHB and on using these and other drugs in the commission of sexual assaults or for other purposes, computers and computer discs.

Depending on the case and its facts, a suspect forensic examination for evidence of the crime should be considered. Performing a suspect examination is sometimes disregarded in drug-facilitated sexual assault cases because the report of the assault is delayed and no evidence is likely to be found on the suspect after several days have passed since he committed the sexual assault.

The role of expert testimony in drug-facilitated sexual assault cases cannot be underestimated. Chemists, forensic toxicologists, and pharmacologists historically have testified in drug trials about their analyses of the particular drug or drugs involved in the case at trial. In a drug-facilitated sexual assault trial these experts will also testify about their analyses of the drug used to rape the victim. In addition to that testimony, these experts can testify how the particular drug affects the body in general, how the victim’s symptoms are typical of someone who has ingested this drug, and can explain the lack of a positive toxicological result in the case. A forensic toxicologist will also be able to testify to possible reasons for a negative result, such as the lapse of time between ingestion and collection of the sample. To explain the properties or effect of the drug, testimony from a scientist with a pharmacological background, who will know more about how the drug works in the body, may be necessary. In the case of negative toxicology results, the pharmacologist can explain that the symptoms experienced by the victim are “consistent” with being drugged with a drug such as a benzodiazepine like drugs.

The challenges presented in drug facilitated sexual assault crimes are not insurmountable. Law enforcement agencies have a variety of investigative techniques available in deconstructing these difficult crimes. It is simply a matter of conducting a thorough and creative investigation. Law enforcement agencies must keep an open mind, understand the patterns associated with sexual assault crimes, and use these patterns to strategize the most effective course of investigation. Drug facilitated sexual assault crimes is an extensive problem and even the lowest prevalence includes a huge number of victims. Hence, stringent measures should be taken for the prevention and control of this hidden public serious health and legal issue in any society. Mass media should play an important role by creating awareness among common people for safe guard of girls and women about accepting drink from tamper-proof bottles and cans, not accepting drinks from unknown persons. In parties sharing or exchange drinks with anyone should be avoided and drink should not remain unattended while talking, dancing, using the restroom, or making a phone call etc to avoid drug facilitated sexual assault crimes.

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