More than two months after the disappearance of Nancy Guthrie, investigators are still searching for answers, but experts say evolving DNA technology could yet provide a breakthrough in the case.
Speaking on Brian Entin Investigates, genetic genealogist CeCe Moore outlined both the challenges and emerging possibilities tied to forensic analysis. She explained that mixed DNA samples, containing genetic material from multiple individuals, remain one of the biggest hurdles in cases like this.
DNA technology
“I think there are a lot of efforts to be able to improve our ability,” Moore told Brian Entin, of de-convoluting mixed DNA samples. “Because we run into that so often with sexual assaults, or as the technology becomes more sensitive with transfer DNA, the ability to detect the tiniest amount of DNA that someone leaves behind really increases the likelihood you’re going to get a mixture, right? Like on a doorknob, for instance.”
She noted that while companies assisting law enforcement are using whole genome sequencing, “there’s really no good techniques to de-convolute on those.” Still, Moore suggested advancements may come sooner than expected.
“I suspect that that has been moved up to right now,” she said. “…So I suspect there are a number of people that are working as fast as they can, trying to figure out a way to work with these more complex mixtures. Nancy’s case is certainly the one that is making this a top priority. But it’s something we really need in the field anyway.”
Investigators are also exploring other avenues. Moore pointed out that a second crime scene, such as a vehicle or another location where Nancy may have been taken, could yield cleaner DNA evidence.
“The really sad part is if they find her body, if she’s deceased, that gives them another opportunity,” she added. “And so, I don’t think it’s the end.”
She further emphasized the importance of revisiting existing evidence if no new scene emerges. “If a second crime scene isn’t found soon or Nancy isn’t found soon, then the next best thing would be to return to that known crime scene to see if they can find DNA. Because if he was there for 40 minutes or 42 minutes, which I’ve heard is a theory, then it’s almost impossible not to leave your DNA behind.”
Chris Nanos addresses limitations
Earlier, Chris Nanos, sheriff of Pima County, acknowledged the technical limitations investigators are facing. DNA samples collected from Nancy’s Tucson home were found to be mixed, complicating efforts to match them through national databases.
“Our lab tells us that there are challenges with it,” Nanos said of the Florida lab processing the DNA, per Fox News. “The technology is moving so fast and in such a frenzy that they think some of this stuff will resolve itself just in a matter of weeks, months, or maybe a year.”
Nancy, 84, the mother of Savannah Guthrie, was last seen at her Tucson home on the evening of January 31. Despite thousands of tips and a $1 million reward offered for information leading to her recovery, authorities have yet to identify a suspect.
