Decontamination of Crime Scene Equipment: Evaluating Current Methods and Determining Best Practices

A 2016 needs assessment conducted by the National Institute of Standards and Technology’s Organization of Scientific Area Committees for Forensic Science (NIST/OSAC) Crime Scene Investigation (CSI) Subcommittee identified the decontamination of crime scene equipment as a gap that must be addressed. Currently, there are no widely accepted standard operating procedures (SOPs) and/or best practices for crime scene investigators to follow regarding equipment decontamination. Furthermore, to date, there has been no peer-reviewed published research to assess the effectiveness of the different decontamination methods that are currently employed by crime laboratories and law enforcement agencies involved in crime scene investigations. Ineffective decontamination of crime scene equipment has the potential to lead to cross-contamination between scenes as well as secondary transfer to evidence after contact with equipment. With increased sensitivity of current DNA analysis protocols, the ineffective decontamination of CSI equipment has implication for wrongful convictions due to potential secondary DNA transfer. To address this gap, and in response to the NIST/OSAC needs assessment, RTI International (RTI) will perform a comprehensive evaluation of several decontamination methods on commonly used CSI equipment to provide the community with evidence-based recommendations of effective decontamination protocols. RTI has identified reusable CSI equipment that is most likely to be contaminated with biological material after use at a crime scene based on literature searches, crime laboratory SOP reviews, and discussions with crime scene practitioners. Ten types of crime scene related equipment will be used to determine the extent of the effectiveness of six frequently used decontamination methods. The total amount of DNA remaining on the equipment after a controlled decontamination will be quantified using Quantifiler™ Trio DNA Quantification Kit, which includes a quality index (QI) that provides an estimation of the quality of DNA in potentially degraded samples. The outcomes of this research will provide the crime scene investigation and forensic DNA communities of the following: 1) an understanding of the possibility of introducing biological contaminants to crime scene equipment during scene processing and the threat of cross-contamination between scenes; 2) a determination of whether the threat of biological contamination varies between equipment; 3) an assessment of the effectiveness of current methods in reducing true contamination threats; and 4) recommendations for the formulation of best practices regarding biological decontamination methods. 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