TUCSON, Ariz. — The FBI announced Thursday it is doubling its reward to $100,000 for information leading to the arrest of anyone involved in Nancy Guthrie's disappearance after releasing new details about a potential suspect.
The search for Guthrie has stretched into its 12th day as authorities scramble to locate the 84-year-old mother of NBC host Savannah Guthrie.
A U.S. law enforcement source told Fox News Digital Thursday that Pima County Sheriff Chris Nanos, who is leading the Nancy Guthrie case, is blocking the FBI from key evidence, Reuters first reported.
The source said the FBI asked Nanos for physical evidence in the case, including a glove and DNA from Guthrie's home, to be processed at the FBI's national crime laboratory in Quantico, Virginia, but Nanos has "insisted instead on using a private lab in Florida."
It is unclear why Nanos may have requested the use of a private lab.
Since Guthrie's disappearance Feb. 1, the FBI said it has collected over 13,000 tips from the public related to the case.
Every tip is reviewed for credibility, relevance and information that can be acted upon by law enforcement, officials said.
Threat Intake Examiners at the National Threat Operations Center (NTOC) and FBI personnel are supporting a 24-hour command post in which dozens of agents and investigators are assigned leads and tips to action each shift.
Anyone with information is urged to call 1-800-CALL-FBI or submit tips at tips.fbi.gov.