TUCSON, Ariz. — On Thursday, the FBI increased its reward to $100,000 for any information that could lead to the capture of those involved in Nancy Guthrie’s disappearance. This announcement came as new insights into a possible suspect were unveiled.

The FBI’s Phoenix division revealed that forensic experts from the Operational Technology Division have verified new “identifying details” from doorbell camera footage related to Guthrie’s alleged kidnapper.

The suspect is described as a male, standing approximately between 5 feet 9 inches and 5 feet 10 inches, with an average physique.

Authorities have also pinpointed the brand of backpack worn by the suspect in footage released earlier this week. It was identified as a black, 25-liter “Ozark Trail Hiker Pack.”

On Thursday, the FBI shared new images of the backpack linked to the Nancy Guthrie case. (FBI Phoenix via X)

As the search for 84-year-old Nancy Guthrie enters its 12th day, efforts intensify to find the mother of NBC host Savannah Guthrie.

A U.S. law enforcement source told Fox News Digital on Thursday Pima County Sheriff Chris Nanos, who is leading the Nancy Guthrie case, is blocking the FBI from key evidence, as first reported by Reuters.

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.

The FBI released new photos of a backpack in relation to the Nancy Guthrie investigation on Thursday. (FBI Phoenix via X)

Since Guthrie’s disappearance on 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.