Nancy Guthrie
Nancy Guthrie

TUCSON, Ariz. — Nearly nine months after Nancy Guthrie vanished from her Arizona home, investigators have sent evidence to four crime laboratories around the country. No suspect has been publicly named and no arrest has been made in the disappearance of the mother of NBC "Today" co-anchor Savannah Guthrie.

Pima County Sheriff Chris Nanos said in a recent radio interview that his department has sent evidence to four specialized labs, including facilities in Florida, Kansas and San Francisco, according to accounts of the interview. Nanos and investigators recently traveled to Florida to meet with a lab analyzing mixed DNA evidence from Guthrie's home.

Authorities have not publicly announced any breakthrough from the testing.

Guthrie, 84, was last seen at her home in the Catalina Foothills near Tucson on the evening of Jan. 31. She was reported missing the next day. Investigators believe she was taken from the home against her will in the early hours of Feb. 1.

DNA at the center of the search

Much of the investigation now hinges on forensic evidence.

Some DNA recovered from the home has not been matched to anyone known to have been inside, according to reports. One lab is reportedly working to separate a DNA mixture from multiple people, while another specializes in obtaining profiles from difficult samples, such as a hair without a root.

Nanos said in July that testing on a hair sample from the home had been inconclusive. Earlier in the investigation, he said investigators had DNA they believed could still produce results.

"We have some DNA that we think is still workable, and we have to work that," Nanos said in March. "We're working with the FBI. We're working with several labs around the country on this."

Retired FBI special agent Maureen O'Connell said on NewsNation's "Brian Entin Investigates" that she was "absolutely gobsmacked" that the unmatched DNA had not yet produced a hit in law enforcement or genetic genealogy databases. She suggested that sending evidence to multiple labs, each with a different specialty, indicates investigators believe the samples are promising.

Unknown male DNA was also found on a glove discovered about 2 miles from Guthrie's home. Two men were briefly detained and later released.

What investigators know

Authorities have said Guthrie did not leave voluntarily. DNA testing confirmed that blood found on the porch was hers. Her phone, wallet and car were left at the house.

On Feb. 10, the FBI released doorbell camera footage showing a masked man outside her home that morning. He was wearing gloves and a backpack and carried a holstered handgun. The person has not been identified.

Nanos has said investigators believe Guthrie was alive when she was taken. She relies on a pacemaker and daily medication, raising concerns about her health from the start.

Family members were cleared as suspects early in the investigation, the sheriff has said.

Remains found nearby

Two discoveries of human remains in the Tucson area have drawn attention, but neither has been linked to the case.

On Oct. 7, a bone fragment believed to be a piece of a human skull was found in a wash in Oro Valley, about 10 miles from Guthrie's home. Police said no other remains were found nearby. The fragment was sent to the Pima County medical examiner. As of mid-October, no findings had been released and authorities had not connected it to Guthrie.

In August, human remains were found in the desert about 15 miles from her home. The sheriff's department said at the time that "there is no indication" they were connected to the investigation.

Ransom notes and scams

The case has been complicated by a series of purported ransom demands.

The first note, sent days after the disappearance, demanded $4 million in cryptocurrency and described Guthrie as "safe but scared." A second note claimed she had died shortly after being taken and said she was "buried in nature now." Authorities released the full text of both notes in July and asked the public to help identify the writer.

The FBI has said some demands were extortion attempts without legitimacy, while others were still being investigated. A man who posed as the kidnapper pleaded guilty in July to federal harassment charges.

In late September, the joint task force said it had learned of "a new possible ransom note related to the Nancy Guthrie investigation" and was reviewing its credibility. Its contents have not been made public.

Former FBI agent Jennifer Coffindaffer said this month that she received four ransom emails about the case in April that demanded bitcoin. She said she came forward because "other people might be contacted and might fall for the ploy." The task force does not consider those messages credible.

Sheriff's officials have urged the public not to send money or personal information in response to unsolicited messages.

Investigation under scrutiny

The sheriff's department has faced criticism over its early handling of the case, including in an August report by The Wall Street Journal. Nanos has defended the investigation and rejected suggestions that it has stalled.

"This case is not cold," he said.

Investigators have received more than 50,000 tips.

Family's pleas

Savannah Guthrie has repeatedly appealed for help finding her mother.

"Someone knows something," she said in August, urging anyone with information to come forward.

In July, she addressed the abductor directly: "Tell us where to look for her."

In September, she said, "We just want our mom home, give her a proper goodbye. That's all."

The Guthrie family is offering a $1 million reward for information leading to an arrest. The FBI is offering up to $100,000.

How to help

Anyone with information is asked to call the Pima County Sheriff's Department at 520-351-4900 or the FBI at 1-800-CALL-FBI.