Deerfield Beach DNA lab assists in search for Savannah Guthrie's mother 23 days after Arizona abduction

More than three weeks after 84-year-old Nancy Guthrie was abducted from her Tucson, Arizona home, there is still no sign of the missing woman.

Guthrie — the mother of "Today" show host Savannah Guthrie — was taken from her home last month, sparking a nationwide search and thousands of investigative leads.

Now, a Deerfield Beach-based forensic lab is playing a critical role in the ongoing investigation.

Investigators with the Pima County Sheriff's Office have submitted evidence to DNA Labs International in Deerfield Beach, where forensic specialists are analyzing materials collected in connection with the disappearance. According to the sheriff's office, the agency maintains a long-standing contract with the independent lab.

Mike Harrigan, a former FBI agent who specializes in cold case investigations, said the lab follows the same methodology and standards used by the FBI.

Still, he cautioned that the presence of biological evidence does not necessarily prove someone committed a crime.

"The sheriff likely has biological evidence," Harrigan said. "But it doesn't mean the person committed that crime."

Authorities have not publicly detailed what specific evidence is being examined. However, with thousands of tips and leads pouring in, investigators face a complex and potentially lengthy process.

"Even when you vet those leads, you have to catalogue everything," Harrigan said. "And all of a sudden a discounted lead could be very important."

All evidence from the crime scene and search warrant scenes has been submitted for analysis. Lab experts are working through that analysis. As with any biological evidence, there can be challenges separating DNA. There are currently no updates regarding this process.

CBS Miami reached out to the Pima County Sheriff's Office for comment on DNA Labs International involvement in the Guthrie case   

This was the response:

"The Florida laboratory was awarded the contract through a competitive bidding process conducted by Pima County. The department has utilized this laboratory's services for many years."

The investigation remains ongoing.