Bone Found Near Nancy Guthrie’s Home, Police Reveal Details of Investigation

The discovery comes as investigators continue searching for the mother of journalist Savannah Guthrie, who has been missing since Jan. 31

Authorities are releasing more details after remains were found near Nancy Guthrie’s Arizona home, as the Today show co-anchor’s mother remains missing.

Volunteers join search for Nancy Guthrie in Arizona

A spokesperson for the Tucson Police Department said a human bone was found on Thursday, May 7 at North Craycroft Road and East River Road — about seven miles from the 84-year-old woman’s house in the Catalina Foothills neighborhood, per a statement obtained by PEOPLE.

The spokesperson described the probe into the finding as a “prehistoric anthropological investigation” and said it was not criminal in nature.

Police added that the University of Arizona Department of Anthropology and the Pima County Office of the Medical Examiner assisted.

The discovery comes as investigators continue searching for Guthrie, the mother of journalist Savannah Guthrie, who has been missing since Jan. 31.

Authorities believe Nancy was kidnapped from her home by a masked man who was captured on surveillance footage outside her front door in the early morning hours of Feb. 1.

Investigators previously said Nancy’s blood was found outside the home, along with “mixed DNA” that is still being tested in hopes of identifying a suspect. A mixed sample contains genetic material from more than one person, making it more difficult to isolate an individual profile, CeCe Moore, chief genetic genealogist at Parabon NanoLabs, previously told PEOPLE.

Sources familiar with the criminal investigation told ABC News in April that the FBI is using more advanced technology to examine the sample, which was received from a private Florida lab that works with the Pima County Sheriff’s Department.

Pima County Sheriff Chris Nanos has said investigators believe they know the motive.

“We believe we know why [the kidnapper] did this and we believe that it was targeted, but we’re not 100% sure of that,” Nanos told NBC News in March. “So it’d be silly to tell people, ‘Don’t worry about it. You’re not his target.’ You could be. Don’t think for a minute that because it happened to the Guthrie family, you’re safe. No. Keep your wits about you.”

A $100,000 reward has been offered by the FBI for any information leading to Nancy’s recovery or an arrest in the case. Savannah and her family have since offered an increased $1 million reward and donated $500,000 to the National Center for Missing & Exploited Children.

Anyone with information about Nancy Guthrie’s disappearance is asked to please contact 1-800-CALL-FBI (1-800-225-5324) or the Pima County Sheriff’s Department at 520-351-4900.