Classification Procedure for Lubricant Stains and Samples Collected from Sexual Assaults

Sexual assaults are an unfortunate reality in modern society, which includes situations in which the assailant is known or unknown. Classifying a sample of an unknown sexual lubricant without directly comparing them to a known sample would provide a capability that has not been operationalized in the United States. Lubricant analysis for identifying and comparing trace amounts in sexual assault cases is relatively new in the field of forensic science, in comparison to other Trace Evidence disciplines. Most research focuses on the identification of trace levels of polymers from the main lubricant component, but it is necessary to identify the necessary parameters to conduct daily analysis of unknown lubricants, i.e., post-coitus residue collection, storage, extraction and identification.

The development of the Sexual Assault Lubricant (SAL) database, provides the foundation of a more objective manner of analysis can be accomplished for forensic lubricant analysis. This database provides the community a way to classify a true unknown sample collected in sexual assault cases; however, to advance this tool forward it is necessary to evaluate the use of this database for real world samples and analysis. A characterization scheme for unknown lubricants has been developed as a result of NIJ grant 2016-NE-RD-0001, but the next step is to define a way to operationalize its use for sexual assault cases. This can be achieved by determining the accuracy of analyzing true unknown and known samples considering that many of the minor and unique components can be absorbed into the human skin or wear away during the act of sex or any appropriate use.

This project aims to develop the necessary guidelines for forensic laboratories to analyze unknown lubricant samples including collection, storage methods, screening methods, lubricant extraction protocols, analysis and classification. Since it is necessary to provide direct comparison between to degraded unknown samples, it is necessary to develop a protocol for degrading known lubricant samples in the laboratory for analytical comparison. This will allow for the determination of false positive and false negative error rates throughout the forensic analytical process. At that end of the project, an optimal collection, storage and extraction protocols will be developed. Additionally, an evaluation of classifying true unknown lubricants that were purchased for this project specifically, and those residues collected after sexual intercourse, will be conducted to determine error rates. Newly acquired lubricant samples will be added to the SAL database at the end of the project.

This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14).

CA/NCF