Preservation of biological samples in sex crimes

Abstract

Introduction: Sexual violence represents one of the most serious issues in public health, social justice, and sexual and reproductive human rights in Latin America. It is defined as the commission of any sexual act without consent or desire from the victim, involves the use of force, and leads to severe physical, psychological, and social consequences. Due to this, the necessity arose to conduct laboratory studies in 1971. In that year, Hara and colleagues described a protein enzyme in seminal fluid named “gammasemino” protein. By 1978, Sensabaugh and others characterized the protein in detail, establishing that its molecular weight corresponds to 30,000 Daltons, and it was named p30. In 1980, the first immunometric assay was developed, and Graves and Sensabaugh demonstrated that p30 is a reliable forensic marker for the identification of semen, thereby proving the identity of the perpetrator of rape. Objective: To determine if the P30 protein maintains the results of evidence obtained in sexual crimes, through adequate preservation in solid containers. Methodology: The current investigation was carried out in the laboratory, for both field and bibliographic methods. Results: The tests carried out in the laboratory of different swabs samples of vaginal secretion, which were collected each 1 year 2 months ago, 2 years ago and 5 years ago when the sample was taken when it was positive; the sample in a latex glove with a cut of 0.5 x 1 cm of the middle part with a conservation time of 4 years 5 months, coincided with the same positive result. That is to say that if an adequate conservation of the P30 protein in solid supports is maintained, the results of the tests obtained in sexual crimes will be the same without any alteration. Conclusion: once the investigation was concluded, it was possible to prove that, if there is a good conservation of the P30 protein without letting it get contaminated, when performing another analysis with the same procedure in the laboratory, over the years we will obtain the same results with high reliability; which will be useful when it is necessary and requested by the competent authority to perform a new study in the laboratory of the evidences that served as support at the time to solve a certain crime of rape. Results: The tests carried out in the laboratory of different swabs samples of vaginal secretion, which were gathered each: 1 year 2 months ago, 2 years ago and 5 years ago when the sample was taken when it was positive; the sample in a latex glove with a cut of 0.5 x 1 cm of the middle part with a conservation time of 4 years 5 months, matched with the same positive result. This means that if an adequate conservation of the P30 protein in solid containers is maintained, the results of the tests obtained in sexual crimes will be the same without any alteration. Conclusion: once the investigation was concluded, it was possible to prove that, if there is a good conservation of the P30 protein without letting it get contaminated, when performing another analysis with the same procedure in the laboratory, over the years we will obtain the same results with high reliability; which will be useful when it is necessary and requested by a competent authority to perform a new study in the laboratory of the evidences that served as support at the time to solve a certain crime of rape.