Police have found mystery DNA in Nancy Guthrie's property which belongs to neither her - nor anyone known to her.
"DNA other than Nancy Guthrie's and those in close contact to her has been collected from the property," the sheriff's department confirmed.
Officials are now attempting to identify the source of the genetic material, but have not revealed where it was discovered.
The mother of Today show presenter Savannah Guthrie disappeared from her Tucson, Arizona home nearly a fortnight ago.
The FBI has joined the Pima County Sheriff's Department in the search - sparking a bizarre row with local police.
Sheriff Chris Nanos was forced to rejected claims that he blocked the FBI from accessing evidence in the case on Friday night.
"We have no glove. We never found a glove on that property," Nanos told Fox News.
"Reports that a glove was found inside the residence or on the property are inaccurate," the sheriff's department added.
Sheriff Nanos was said to have refused to allow the FBI to examine a glove and DNA at its Quantico laboratory, instead sending the material to a private Florida facility.
The FBI released images of a black backpack wanted in connection with its probe
|FBI VIA REUTERS
But he dismissed this as "not even close to the truth".
"Actually, the FBI just wanted to send the one or two they found by the crime scene, closest to it - mile, mile and a half... I said 'No, why do that? Let's just send them all to where all the DNA exists, all the profiles and the markers exist.' They agreed, makes sense," he told KVOA.
The FBI has released additional details about the suspect in the disappearance.
The Bureau described the individual as male, standing between five feet, nine inches and five feet, 10 inches tall, with an average build.
LATEST ON NANCY GUTHRIE:
Authorities have been seen at the Guthrie residence since Nancy's disappearance on January 31 | REUTERS
PICTURED: Nancy and Savannah Guthrie on the Today show set | GETTYInvestigators also shared photographs from various angles of a black 25-litre backpack identified as an "Ozark Trail Hiker Pack".
The agency confirmed this is the brand and model the suspect was carrying.
FBI Phoenix has raised its reward for information about Guthrie's disappearance to $100,000 (£73,000).
Multiple gloves were discovered during the search, located between roughly two and ten miles from the missing woman's residence.
Investigators planned to return to Guthrie's home on Friday to analyse security camera footage in detail.
On Tuesday, officials released images of the suspect in her kidnapping for the very first time | FBI VIA REUTERS
Sheriff Nanos recently revealed that Savannah Guthrie texted him
| INSTAGRAM/SAVANNAHGUTHRIE"It is really about just taking that video and frame-by-frame and trying to get as much out as we can," Sheriff Nanos said.
He told ABC News that officers would attempt to determine the weight of the suspect captured on camera.
But the police chief added that he remains hopeful that progress is being made in locating the missing woman.
Using DNA samples from family members and household staff, investigators will work to eliminate individuals from their enquiries.
Sheriff Nanos recently revealed that Savannah Guthrie even texted him, but said "she has her own people and didn't need him".