Nancy Guthrie missing: Forensic scientist encourages new investigative approach since case 'isn't cold yet'

Valentin, who's chair of the Forensic Science Department at the University of New Haven's Henry C. Lee College of Criminal Justice and Forensic Sciences, said on the "Crime and Justice" podcast that a fresh set of eyes might be needed.

The forensic expert is very confident that there is some type of evidence left behind by whatever individual is suspected to have taken Nancy Guthrie from her home.

"Because if people went into that home, and we believe they did, right? To take her from that house, there must be evidence of their presence in that home. Where is it? What is that evidence? We need to find it," he said.

He also cautioned that the key piece of evidence that breaks the case might not be "obvious."

"It's not going be the obvious DNA profile somewhere, it is not going to be the obvious latent fingerprint. It's probably some of the things that we've probably not used as much, right? The hair, the fibers, the other kinds of trace evidence. But we've got to start cobbling together all the forensic evidence we have at our disposal to move this case forward, because otherwise it might not move forward," Valentin said. 

Guthrie posted a segment from the "Today" show where viewers were shown how to submit tips anonymously. She said that tips can be anonymous "and likely paid in cash."

People with information about Nancy Guthrie's disappearance are asked to contact 1-800-CALL-FBI.