VCU forensic science researchers receive $2.28M for crime scene evidence research

VCU was one of only four schools in the country to receive multiple awards from the National Institute of Justice.

Tracey Dawson Cruz, Ph.D., sitting in a medical laboratory room.
Tracey Dawson Cruz, Ph.D., professor and chair of the Department of Forensic Science, received a nearly $400,000 award to develop an assay that can determine earlier on in the normal forensic DNA workflow if the DNA in the evidence sample is from a single individual or is from more than one individual. (Contributed photo)

Researchers in the Department of Forensic Science in the College of Humanities and Sciences have received four grants totaling $2.28 million from the National Institute of Justice to launch studies focused on the development and evaluation of forensic tools for examination of physical evidence. The National Institute of Justice is the research, development and evaluation agency of the U.S. Department of Justice.

Virginia Commonwealth University was one of only four schools in the country to receive multiple awards from NIJ during its 2019 funding cycle for forensic science applications. During this cycle, 46 grants were awarded to 28 universities. VCU received more awards and total funding for forensic science research than any other university this year.

Michelle Peace, Ph.D., associate professor in the Department of Forensic Science, received a $1.24 million grant for her study investigating e-cigarettes and ethanol, which is often added as an unlisted ingredient in e-liquids. Peace’s grant is the largest single award in the department’s history.

Associate professor Christopher Ehrhardt, Ph.D., received a nearly $500,000 grant for his study, “Determining Time Since Deposition of Epithelial Cell Samples Using Intrinsic Fluorescence Signatures.” The goal of the project is to develop a method to determine how long “touch” evidence has been at a crime scene prior to its collection.

“Most current techniques for DNA profiling can only be used for identification (i.e., whose DNA it was) but they cannot tell you when the DNA got there,” Ehrhardt said. “As such, this is one of the most common defenses used to refute DNA evidence in court. Something along the lines of, ‘Sure my client’s DNA was found at the crime scene, but that’s only because he attended a party at the same house months earlier.’”

Ehrhardt’s lab has recently focused on identifying biological markers within the cells that degrade over time.

“We can measure the abundance of these compounds indirectly through their fluorescent signatures and get a sense of how long they have been degrading in the environment, and therefore how long ago they were left at the crime scene,” he said.

Christopher Ehrhardt, Ph.D., conducting testing in a scientific laboratory.
Christopher Ehrhardt, Ph.D., an associate professor in the Department of Forensic Science, received a nearly $500,000 grant to develop a method to determine how long “touch” evidence has been at a crime scene prior to its collection. (Photo by Kevin Morley, University Relations)

Tracey Dawson Cruz, Ph.D., professor and chair of the Department of Forensic Science, received a nearly $400,000 grant for the development of an assay that can determine earlier in the normal forensic workflow if the DNA in the evidence sample is from a single individual or more than one individual. Having that information earlier, rather than at the end of the analysis, would allow examiners to make decisions about how they triage or combine samples, or even if the sample should move forward for analysis.

“Mixtures in DNA profiles increase the complexity of the interpretation and often lead to inconclusive results,” Dawson Cruz said. “Consequently, analysts will swab only very small areas of evidence surfaces in order to avoid creating mixtures. Unfortunately, this often leads to very low yield DNA samples with difficult to detect DNA profiles — and this determination is only made after the sample has been completely consumed. Having earlier knowledge that multiple samples from the same item are single source, and likely from the same individual, would allow the analyst to combine those swab samples more confidently, providing more DNA for analysis and, more likely, a successful profile without the fear of creating a mixture or sample consumption.”

Dawson Cruz’s project is an ongoing collaboration with the Bureau of Alcohol, Tobacco, Firearms and Explosives laboratory. She developed the assay with Edward Boone, Ph.D., professor in the Department of Statistical Sciences and Operations Research in the College of Humanities and Sciences.

The fourth NIJ grant was awarded to Sarah Seashols Williams, Ph.D., assistant professor in the Department of Forensic Science, in support of her research into using microRNAs to identify body fluids left behind as evidence, a project that started in collaboration with Zendra Zehner, Ph.D., a retired professor in the Department of Biochemistry and Molecular Biology in the School of Medicine.

“This new grant funding will allow us to explore an interesting advantage of miRNAs: they are present and detectable in DNA extracts, which seems like a minor issue, but actually is a distinct advantage for forensic use,” Williams said.

When evidence comes into the lab, the DNA is extracted to develop a DNA profile, Williams explained. RNA analysis typically requires a separate time and sample-consuming reaction, which is the main reason that forensic labs in the U.S. don't use RNA for body fluid identification, she said.

“An additional extraction takes time and resources needed to reduce backlogs, and we often don't have enough sample to do more than one extraction,” she said. “So evaluating the body fluid identification potential of microRNAs in DNA extracts could allow for rapid implementation of a molecular body fluid [identification] method in the forensic community. There is nothing beyond basic catalytic tests for body fluid identification right now.”

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