Sheriff explains where the Nancy Guthrie search stands on Day 100

The Arizona sheriff helming the investigation into Nancy Guthrie's disappearance gave an update about where the case stands on its 100th day.

In an interview with local station KOLD published May 12, Pima County Sheriff Chris Nanos reaffirmed that both local investigators and the FBI remain actively involved in solving what happened to the 84-year-old mother of "Today" anchor Savannah Guthrie.

"They are working hard to get this resolved, and I think every day they get closer," Nanos told the outlet.

Savannah Guthrie's elderly mother was last seen Jan. 31 before an apparent kidnapping in her Catalina Foothills neighborhood directly north of Tucson, Arizona.

Nanos rejects the claim that FBI was kept out of investigation

Nanos confirmed that the FBI has been involved since "Day One," and said authorities are working with labs on both the "digital end or the biological end, DNA."

"It moves at a snail’s pace, I guess for some," he continued. "But for my investigative team, and for me, we look at this as, no, this is doing exactly what we need it to do."

FBI Director Kash Patel has criticized the Arizona department's handling of the investigation and on a May 5 episode of "Hang Out with Sean Hannity," alleged that the department attempted "to keep [the FBI] out" early in the case for four days.

In a statement provided to USA TODAY, the Pima County Sheriff's Department confirmed Nanos was aware of the interview and wrote: "While the FBI Director was not on scene, coordination with the Bureau began without delay."

Sheriff to testify about his work history to the board of supervisors

Nanos' recent remarks come as a bipartisan pair of Pima County supervisors continue their campaign to remove him from office. The sheriff has faced mounting backlash over misrepresenting his work history in a sworn deposition, on his public résumé, in media interviews and in a report to county leaders.

The Democratic-majority Pima County Supervisors' Board voted unanimously on May 12 to use an old territorial law to compel Nanos to give a sworn testimony about his work history and other matters.

Democratic Supervisor Matt Heinz and Republican Supervisor Steve Christy, who have both called on Nanos to resign, were both present when their board met on May 12.

"There really is no wonder why we're having such a horrible and horrific time trying to solve this very tragic case, and it's really laid directly on the sheriff's shoulders," Christy said.

The backlash over Nanos's conduct escalated after Pima County Assessor Suzanne Droubie accused Nanos of scolding her for complying with an FBI request because it created more leads for his department to pursue in the Guthrie case.

Evidence found in the Nancy Guthrie case so far

Law enforcement previously confirmed that the blood found on the porch of the home belonged to Nancy Guthrie and that authorities also found DNA evidence in the home that did not belong to her or those close to her.

On Feb. 10, the FBI released doorbell footage of the suspect, described as a "male, approximately 5'9"-5'10" tall, with an average build," at Guthrie's front door the night she went missing.

A pair of black gloves that seemingly resembled the gloves the suspect wore in the video did not match any entries in the FBI's Combined DNA Index System, or CODIS, according to the sheriff's department. Neither did the DNA found at the property.

Savannah Guthrie shares message of hope amid mom's disappearance

After stepping back from the "Today" show in February, Savannah Guthrie returned to the show in April and has remained on the air ever since.

On May 13, she took to her Instagram story with a hopeful message. Guthrie reshared a post from her "Today" colleague Carson Daly, who cited a Bible verse and the quote, "Keep praying, no matter how hopeless life may seem. God can change your entire life in a single moment."

"Bring her home," Daly added.

Guthrie previously shared a touching tribute to her mom on Mother's Day. In the caption of a clip compiling videos and photos of Nancy Guthrie, the "Today" anchor wrote, "Mother, daughter, sister, Nonie - we miss you with every breath. We will never stop looking for you. We will never be at peace until we find you." She added, "Please keep praying. Bring her home."

Contributing: Stephanie Murray, Arizona Republic; Brendan Morrow, USA TODAY