Semen body fluid identification remains a critical aspect of the forensic investigation of alleged sexual assaults. Over the years, as advancements have been made in the area of forensic science, several different methods for semen identification have been utilized. It is not unusual for several methods of semen identification to be incorporated into a single sexual assault investigation. Most methods of semen identification are based on either detecting enzymatic activities or are targeted at specific cells or antigens. Other methods have evolved utilizing fluorescence or protein expression. Presumptive tests are often used to screen or locate semen staining. Further confirmatory tests can be used to identify the staining as semen and finally the donor of the stain can be further identified through DNA analysis. For routine application of these methods, they need to be specific, sensitive, cost effective, easy to use, and nondestructive. Although new techniques are being researched, it appears that traditional methods of semen identification remain the most widely applied in forensic casework.
This article is categorized under:
Forensic Biology > Body Fluid Identification
Hash oil samples were analyzed for pollen before and after filtration through 12 different household fabrics, to determine to what extent such samples can be shown to have come from the same source despite having undergone these different treatments. Unfiltered hash oil samples extracted from the same batch of cannabis leaf material showed similar pollen values. An unstirred portion of the extraction solution showed differences in some pollen values to those of stirred samples, suggesting differential rates of pollen settling. However, the presence of some of the same uncommon pollen types in unstirred and stirred samples suggests a common source. Of 12 filter fabrics, ten (a bath towel, two tea towels, a bedsheet, two pillowcases, three stockings and a t-shirt) had a minor effect on the pollen content of the hash oil by slightly reducing the frequencies of some of the larger sized pollen types. Only two of the fabrics had a major effect on the pollen content of the hash oil. The nappy markedly reduced the proportion of the larger sized pollen types resulting in a marked increase in the proportion of some smaller pollen types whereas the calico filtered out virtually all pollen. Illicit hash oil samples recovered from different people or places may therefore in many cases be compared to determine a common source despite samples from the same batch having undergone different filtration treatments and despite differential settling rates of pollen. Also, hash oil samples may be compared to samples of untreated cannabis leaf material to establish a common source.
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