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Cold chain has a key role in forensic research and criminal proceedings

NIST discusses how temperature-controlled storage and transportation impacts the integrity of biological evidence collection and its effect on criminal proceedings

| | Sep 27, 2018 | 9:00 am
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Maryland, USA, 27 September 2018: A secure cold chain underpins the integrity of food, medicine, even artwork. In addition, it is equally instrumental in the field of forensics. Temperature controls in this industry can have alarming ramifications in evidence collection and, in some cases, determine the conviction, or exoneration, of an individual. Shannan Rene Williams, Project Manager for the Special Programs Office, Forensic Science Research Programme, National Institute of Standards and Technology (NIST), a laboratory, and non-regulatory agency of the United States Department of Commerce, discussed the role that temperature and environment plays in maintaining the integrity of evidence, and the need for guidelines in the sector.

Williams stressed that forensic science is mainly concerned with maintaining the integrity of evidence throughout the entire chain of custody. “If a crime has occurred and there are different types of evidence, including biological, when you test it, you have to make sure your analysis is correct,” she explained. “This is where temperature and environmental conditions are important. If evidence has forensic value, you do have to consider the temperature at which it’s being stored, so you can ensure the correct results.” This varies, she said, based on the type of DNA evidence, be it blood, or, as an example a wet piece of t-shirt used to extract DNA, all of which must  be stored at different conditions. “DNA evidence is very important in the criminal justice system,” she said. “It is used to identify or exonerate individuals. If biological evidence is not stored appropriately, there is a lot of risk associated with it. The biggest risk is not getting the right result.”

Williams also pointed out that forensic evidence is unique in that, once it leaves an agency’s control, there isn’t a stringent mechanism for accountability, adding that another major challenge is ensuring the climate is maintained as it is transported to the next location, be it a lab, or a courthouse. In certain situations, Williams said, some samples of evidence that are not handled or stored properly, and undergo temperature and humidity abuse, may make it harder to find the DNA [in those samples].

Williams stressed that NIST is committed to pushing forward best practices in terms of appropriate short- and long-term storage conditions, adding there was no consistency in terms of proper protocols in evidence rooms, by way of nation-wide standards, which is what led the organisation to develop The Biological Evidence Preservation Handbook. “We don’t advocate a particular standard, but we do propose some minimum standards based on scientific review, on what should be frozen, refrigerated and the necessary temperature controls. Labs are on the way to try and document how it’s stored, but there’s lots of room for improvement. It is important to raise awareness on the issue of making sure evidence is managed in a lifecycle across all the agencies.” Williams added, the standards, which NIST is promoting, are voluntary, but that the handbook is available for everyone and has been translated in many languages, for countries to consider adopting it for use.

Essentially, Williams said, it is difficult to specify equipment for laboratories, given the vast range of law enforcement agencies, which determines the level of investment provided for the training and equipment in evidence storage. Some, she said, can use regular home refrigerators as evidence storage devices, while others can have entire rooms. “The level of investment is a challenge across the board,” she said. “Property and evidence tend to be overlooked. We hear agencies that don’t have resources in facilities that can maintain constant temperature x, y and z. Ideally, you would have an entire property evidence room. At least have some temperature control, if not refrigeration, but that is a challenge, especially for agencies with millions of items. They can’t afford the cost of maintaining such a large facility, with adequate temperature and humidity controls.” The standards, she said, are part of efforts in the evidence-awareness programme to encourage greater investment in resources.


Hannah Jo Uy is Assistant Editor at Climate Control Middle East magazine. She may be contacted at hannah@cpi-industry.com

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