Diving deeper into new frontiers of forensic biology
Figuring out whose DNA is found at the scene of a crime is a routine task for crime labs.
But what kind of tissue is the source of that DNA? And how long has it been there?
That’s more difficult to determine. And courts that have historically focused on the “who” increasingly care about the “what” and “how.”
“Crime labs have the equipment to test DNA, but their technology unfortunately leaves judges and juries’ questions about the circumstances of its deposition unanswered,” explains Kate Philpott, a Virginia-based scientific and legal consultant and affiliate faculty in the Department of Forensic Science.
There, she’s worked for nearly a decade with forensics professor Christopher Ehrhardt, Ph.D., developing a technology to analyze “non-genetic attributes” of cells within forensic evidence. They hope to bridge the current gap in knowledge about biological evidence found at crime scenes.
Those unknowns — sample age, where it came from — often create a gray area where factfinders are essentially left to guess about the reliability of critical elements of allegations. It’s a particular problem, given prosecutors bear the burden of proving their case beyond a reasonable doubt, Philpott says.
To uncover those answers, the pair are researching applications of flow cytometry, a technique that analyzes fluorescent and scattered light signals produced by cells and particles as they flow past a laser beam. The signals are analyzed through machine-learning algorithms that compare the properties to a database of cells where factors like age, tissue source or the presence of environmental compounds are known. The aim is for the software to differentiate cells of unknown origin.
Ehrhardt is the co-founder of a company, Rapid Forensic Cell Typing, that is exploring real-world use of the technology in the legal system. RFCT’s technology is used to provide information about biological samples before time-consuming and expensive DNA testing is performed.
“It will allow forensic labs to quickly determine the value of a sample before it gets to DNA profiling, which can make crime labs more efficient and reduce delays in the legal system,” says Ehrhardt, whose lab is housed at the VCU College of Humanities and Sciences.
Philpott notes their work could also address two societal issues within the justice system: An individual's constitutional right to a speedy trial, and inherent human biases in law enforcement when gathering and processing evidence. Backlogs in processing DNA evidence can lead to extended jail time for individuals who are presumed to be innocent until proven otherwise, too.
The company’s IP could also serve a profit center for crime labs that choose to integrate it into their services, particularly privately funded ones that compete for business from legal stakeholders. “Prosecutors, defense attorneys and police alike have expressed a strong interest in the information that RFCT’s technology is able to provide,” Philpott says.
As a company, RFCT plans to provide an online subscription to crime labs to access the technology. The company is conducting testing and analysis to attract trial users. This year, RFCT was awarded a $270,578 grant from the National Science Foundation to further test its technology.