The fifth day of Nancy Guthrie’s disappearance has nearly passed – but investigators are still working hard following leads as the family continues to plead for help in finding their beloved mother.

Investigators are looking for any video surveillance in an area with dense vegetation and limited lighting as they work against the clock to find Guthrie, whose heart condition adds another level of anxiety in their search. Meanwhile, authorities are working to determine if several ransom notes distributed to media outlets are legitimate, leaving a son begging for contact as the first deadline has passed. A person was also arrested for a different, illegitimate ransom threat, according to authorities.

Here’s the latest on Guthrie’s disappearance:

Security has been stepped up at NBC’s “Today” show this week as Savannah Guthrie’s co-hosts and colleagues cover her mother Nancy’s apparent abduction, two people at the network said on condition of anonymity.

The additional security measures were implemented out of an abundance of caution, and may help to alleviate some of the stress that the show’s hosts are feeling, as they talk on air every morning about the unsolved mystery.

Journalists at NBC and elsewhere continue to wonder if Nancy Guthrie was targeted due to Savannah’s high profile TV job, though local authorities have said there is no “credible information” pointing that way.

Major networks like NBC have security departments that support the hosts – from physical protection to online threat tracking – and liaise with local police.

On Monday morning, when the nation first learned of Nancy Guthrie’s disappearance, Pima County Sheriff Chris Nanos mentioned that Savannah’s “security team” had “been in touch with us throughout the night.”

CNN chief law enforcement and intelligence analyst John Miller appears on CNN on Thursday, February 5, to discuss the disappearance of Nancy Guthrie.

CNN

The potential abductor or abductors of Nancy Guthrie are putting her family “in a real box” by not participating in two-way communication so far, CNN chief law enforcement and intelligence analyst John Miller said.

The alleged ransom letter sent to TMZ indicated the Guthrie family would have no way of contacting them, the media outlet’s founder, Harvey Levin, said.

“Saying there’s not going to be another communication and these are the demands and these are the consequences puts the family in a real box,” Miller said.

The Guthrie family have posted two videos so far on social media, indicating they are willing to talk but that they need to know their mother is alive. The most recent video was posted at 5:00 p.m. local time, which was the first deadline given in the ransom note sent to media outlets, FBI Special Agent in Charge Heith Janke said.

The family is “doing something that that I would do, which is they’re talking through the deadline and they are setting a perimeter,” Miller said.

Jonathan Wackrow, a former Secret Service agent, said “all of this is psychological” and the letter is intended to pressure the family to send money right away, without proof that the writer of the letter actually has their mother.

Ultimately, it will be the family’s decision whether or not to pay the ransom, Miller said. The FBI will advise them, but “the family is under a tremendous amount of pressure.”

Danny Harnden, a friend of Savannah Guthrie, appears on CNN on Thursday, February 5.

CNN

A friend and former colleague of “Today” show host Savannah Guthrie shared insight into the strong relationship she has with her mother, Nancy, who he said was proud of her.

Savannah Guthrie has “been through a lot of tough stuff,” Danny Harnden said while speaking with CNN’s Erin Burnett. He added those tribulations have shown “Savannah has what her mom has: the perseverance to get through hard times, the joy, the spirit, the bubbly nature, the smile, the faith in God that they both share as well.”

He also noticed a key word used in the video Savannah Guthrie and her siblings posted last night.

“Last night we heard Savannah say mommy, and it doesn’t matter how old we get, there’s still our mommy, and we’re still their kids,” he said.

TMZ founder Harvey Levin appears on CNN on Thursday, February 5, to discuss the ransom letter for Nancy Guthrie that was sent to TMZ.

CNN

The alleged ransom letter sent to media outlet TMZ indicated the Guthrie family would have no way of contacting Nancy Guthrie’s purported abductor or abductors, founder Harvey Levin told CNN’s Erin Burnett on Thursday.

Levin added whoever sent the email to TMZ went to great lengths to remain anonymous.

The letter begins by stating Nancy Guthrie is “OK, but scared,” Levin said, adding his team immediately sent the letter to law enforcement.

Levin said the letter included one detail that has not been reported: the placement of Nancy Guthrie’s Apple Watch.

The note also included two deadlines — one at 5 p.m. Thursday and one on Monday, officials said.

“The second deadline is far more consequential,” Levin said without elaborating.

KOLD anchor Mary Coleman, who also received the letter, said she has not received any new communication.

“I’ve been refreshing my email constantly to try and see if we’ve received anything. I have my email open right here and we haven’t received anything just yet,” she said.

Coleman said she also hasn’t heard any new information about the ongoing search or investigation and added law enforcement personnel are still present at all of the scenes.

“The captors say she’s OK, but when you also confirm that her blood was found at the doorstep, there are numerous things that are very concerning about the entire situation,” Coleman told Burnett.

Video credit: Savannah Guthrie/Instagram

Camron Guthrie, the son of Nancy Guthrie, issued another plea for the return of their mother on his sister’s Instagram account.

“Whoever is out there holding our mother, we want to hear from you,” he said. “We haven’t heard anything directly. We need you to reach out and we need a way to communicate with you so we can move forward.”

“But first we have to know that you have our mom. We want to talk to you, and we are waiting for contact,” he said.

The video was released at 5:00 p.m. local time, which was the first deadline given in the ransom note sent to media outlets, FBI Special Agent in Charge Heith Janke said during a news conference today.

A security camera at Nancy Gutherie’s house detected a person in the middle of the night Sunday, but there was no video to show who — or what — exactly triggered the alert, officials said.

The camera software detected a “person on camera” at 2:12 a.m., Pima County Sheriff Chris Nanos said.

“There’s no video available. They had no subscription, and therefore it would rewrite itself, cut up. It just kind of loops, right, and covers up. That’s what our analysis teams have told us,” Nanos said at a news conference today.

With no way to see what happened, the sheriff said it’s also possible the camera was triggered by something else moving, like an animal.

Investigators sent what information they had to an external company, but they weren’t able to pull anything else from it, he later told CNN. But the sheriff said, “We’re not done with our efforts in that.” Officials are looking to see where else they can send the camera.

Officials have not confirmed what brand of camera Gutherie had at her house, but several of the most popular have subscription models.

In the case of Ring cameras, events triggered by motion are only recorded after the owner has an active subscription, according to its website. That recording is stored in the cloud for up to 180 days, the company says.

With a new Google Nest model, users can only view up to three hours of event video without a subscription, the website says. Older Nest cameras won’t get video clips without paying.

Guthrie had more than one camera around the property, officials said. The camera was previously in the “front door area” of the house is the only one that is known to be missing, Nanos said.

An undated photo shared on Instagram shows Savannah and Nancy Guthrie

From Savannah Guthrie/Instagram

Five days into the search for Nancy Guthrie, officials say investigators are confronting a range of challenges in locating the 84-year-old mother of “Today” anchor Savannah Guthrie.

The Tucson Sector Border Patrol Search Trauma and Rescue team joined the search on Thursday, a US Customs and Border Protection spokesperson confirmed to CNN. The agency is now working alongside the Pima County Sheriff’s Department, which is investigating the case jointly with the FBI.

Despite the wide-ranging resources devoted to the search, officials say difficult terrain, sparse evidence, no identified person of interest and uncertainties surrounding the ransom letter are hindering investigators’ progress in uncovering crucial details.

The area where Guthrie went missing is “a very suburban, rural area of the Tucson area, in a very mountainous side of town where vegetation is extremely thick,” Pima County Sheriff Chris Nanos told CNN on Thursday, adding that the neighborhood is “not very well lit.” He said investigators are still canvassing neighborhoods and reviewing footage from street and intersection cameras, though the terrain has made surveillance challenging.

Other obstacles include limited evidence. Nanos said DNA results from what investigators considered “the best target” for suspect DNA were minimal, and the blood found on Guthrie’s porch “came back to Nancy.” Referring to crime scene and lab work, he added, “These things are done in an hour on ‘Law & Order.’ This is real world, and it just takes some time. We’re waiting for that one big break. I just hope it comes faster.”

Adding to the uncertainty, authorities say while a ransom letter has been sent to media outlets, there has been no proof of life or follow-up communication from the sender, leaving investigators and the family without clear leads. The ransom letter included two deadlines: the first at 5 p.m. Thursday and the second next Monday.

Investigators are trying to verify any potential proof of life given advances in AI that can make videos appear real, FBI Special Agent in Charge Heith Janke said during a news conference Thursday. An arrest has also been made in connection with what Janke called an “imposter ransom demand.”

The FBI has deployed crisis negotiators, including personnel brought in from Quantico, Janke said, declining to provide further details about their role.