A hair sample that underwent forensic testing after being found at the Tucson, Arizona, home of Nancy Guthrie, the missing mother of “Today” show co-host Savannah Guthrie, came back inconclusive and did not point to a suspect, the sheriff overseeing the local investigation told CBS News on Thursday. 

“It came back with no results,” Pima County Sheriff Chris Nanos said. The sheriff’s department said the results from the hair sample were verified in early June. Thursday was the first time they shared that information publicly.

Nanos noted there was blood and other DNA found at the scene that is also still being analyzed, but has so far also yielded no results.

“I know that there was blood at the scene and so that was also part of the processing of the scene,” Nanos said.

CBS News previously reported in May that a DNA sample that was sent by sheriff’s detectives to a private laboratory in Florida was then forwarded to the FBI’s crime lab in Quantico, Virginia. Officials did not confirm, however, any details about that sample or whether it was the hair sample in question.

“We have a lot of DNA that is being looked at by credible scientists around the country who know and understand what they have in front of them and they understand the rules that they have to play by,” Nanos said.

Nancy Guthrie, 84, was last seen on the evening of Jan. 31 when she was dropped off after dining at the home of her daughter Annie. Security video from Nancy Guthrie’s home showed a suspect at her front door in the early morning hours of Feb. 1.

Investigators have said they believe Guthrie was likely abducted, and at least two ransom notes were sent in the days after she went missing.

“Even when a case goes cold, we don’t give up on it,” Nanos said. “We continue to work it. This one’s far from being cold. God forbid this ever takes 50 years, but it could.”

Other than the surveillance video from Guthrie’s home that was released earlier in the investigation, no new video has been recovered. And it appears the suspect or suspects evaded traffic cameras.

Asked if he believes the suspects could be local to the Tucson area, Nanos said “absolutely.”

“Do I have evidence of it? No,” Nanos said. “But let’s look at crime across the country, around the world, who by far, 90%, 95% of your criminals are where? Right here locally.”

On Monday, Savannah Guthrie posted a video to social media directed at her mother’s kidnappers.

“So I’m asking you, begging you to do the right thing now,” she said in the clip. “Make the right choice. Help us find her. Tell us where to look for her. I truly believe it is never too late to do the right thing.”

The sheriff on Thursday also addressed the criticism that was previously levied against him by FBI Director Kash Patel, who claimed the sheriff’s department was slow to involve the FBI in the case.

“I’ve never talked to him,” Nanos said of Patel. “No, I have no reason to. If I needed him, I’m sure I could talk to him. What I need is to know that his team and my team are working close together and that absolutely they are and they have been for decades.”

Nanos said he is optimistic that the case will be resolved “based on all the evidence before me.”

“The bottom line here is this: We know more than you will ever know, because that’s how investigations work,” he said.