It was meant to be a night like any other, spent eating and laughing in the company of family.
On January 31, Nancy Guthrie visited her daughter, Annie, and played games at her house before she was driven home by her son-in-law, Tommaso Cioni.
He watched from his car as she walked to her garage and safely entered her house in the Catalina Foothills neighbourhood of Tucson, Arizona, police told the New York Times.
It was one of those everyday occurrences that would not have been all that memorable, had it not been the last time anyone saw or heard from Nancy Guthrie.
Not long after she was dropped off and entered her property, the 84-year-old disappeared.
"We know she didn't just walk out of there," Pima County Sheriff Chris Nanos later said in a press conference.
"She did not leave on her own."
Family members grew concerned when friends told them Nancy failed to show up for a virtual Sunday church service the next morning and reported her missing that afternoon.
"She was taken, and we don't know where," Nancy's daughter, Savannah, said in a video update last week.
The story of the missing mother spread quickly online, particularly in the corners of the internet with an unquestionable appetite for true crime.
Savannah Guthrie is the co-anchor of one of the highest-rating morning television shows in the United States. She is beamed into Americans' living rooms every morning and her fame has fuelled the nation's obsession with her mother's disappearance.
But the very nature of it and the many mysteries that remain have also ratcheted up the interest in the case that has now been open for almost two weeks.
Thousands of public tips have poured in, providing all levels of law enforcement with leads to chase down.
There is a $US100,000 ($141,000) reward for information, desperate pleas from her family to her alleged kidnappers, and new grainy video that might unlock it all.
The small county sheriff's department called in the Federal Bureau of Investigations (FBI) and US President Donald Trump has even weighed in, cryptically remarking that "we could have some answers coming up very soon", without providing further details.
But for it to be a kidnapping, this case is missing something rather vital.
To target a famous family, violently seize their matriarch and hold her hostage, a perpetrator would be expected to also issue clear demands for what they want in exchange for her release and exactly how to deliver it.
But that has not happened. What was thought to be a ransom request, police now say turned out to be a cruel opportunistic hoax.
And as the days have dragged on, Nancy Guthrie's family, as well as law enforcement, are without a regular and clear way to contact the people who might have taken her.
So what initially seemed like a high-profile kidnapping that might be resolved with a multi-million-dollar bank transfer, has now morphed into something else and, as former investigators have explained, it might be the combination of intense public interest and "gumshoe detective work" that solves it.
Nancy was 'taken out of her home'
Authorities believe Nancy Guthrie went missing during a 41-minute window in the early morning of February 1, about four hours after she said goodbye to her son-in-law.
It was some time between 1:47am, when her doorbell camera was disabled, and 2:28am, when authorities said the app on her pacemaker disconnected from her phone.
Family members arrived at Nancy's home many hours later, at 11:56am, after they were tipped off that the 84-year-old had not made it to a church service. Minutes later a call was made to 911.
The items they found inside were the first sign something was wrong.
Her phone, wallet, hearing aid, daily medication and car were all left behind and there was evidence of forced entry at her house.
DNA tests of blood found on her front porch came back as a match for her, police said.
"We believe she was taken out of the home against her will, and that's how this investigation is moving," Sheriff Nanos said on NBC on February 2.
Over the following days, the quiet street in Tucson where Nancy lived erupted with activity.
The desert-bound neighbourhood is famed for its sparse landscape, fanlike cacti and breathtaking views of the Santa Catalina mountains.
But as law enforcement officers picked through the shrubbery surrounding Nancy's home in search of a lead, the area attracted a new level of notoriety, drawing with it a throng of journalists and camera operators.
They watched as the yellow tape around Nancy's front porch was put up, pulled down, and put back up again.
"It's unusual because we really haven't had a kidnapping like this in a long, long time. [One] that's involving a celebrity family," Michael Alcazar, a former NYPD detective and adjunct professor of criminal justice at the John Jade College in New York City, told the ABC.
"It's a circus now. They released the crime scene, the media has been walking all over the crime scene. Now they're looking in the backyard and the desert very close to Nancy's residence. They're kind of doing it in reverse."
About the decision to close the area to the public, reopen it and close it again, Sheriff Nanos said: "At the start of this thing, we weren't sure what we had."
In the days following Nancy's disappearance, the sheriff's department picked up the phone to the FBI.
The agency has federal jurisdiction to investigate kidnappings across the US. This became law in 1932 after the baby son of world-renowned aviator Charles Lindbergh was snatched from the family's sprawling New Jersey estate in what was dubbed "the crime of the century".
When the FBI arrived in Pima County, it brought with it technical and forensic expertise in abundance.
Former FBI executive and experienced investigator of abduction cases Katherine Schweit told the ABC the celebrity factor would put the local sheriff "under a magnifying glass".
"As a longtime FBI person, we're used to being under a magnifying glass and every movement we make is tracked. The local sheriff may be less expecting to have 100 different media outlets standing in front of them at a press conference," she said.
"It's really a big jigsaw puzzle. And that's very typical of every investigation where we're simply looking for a bad guy."
One piece is the perpetrator themselves, another is the element of ransom and a family wondering what it will take to bring their missing loved one home.
The gap in the case
American Today show host Savannah Guthrie is well loved and, as one of NBC's top on-air talents, it is well known she has a multi-million-dollar contract.
The family has a connection to Australia, with Savannah born in Melbourne in the early 1970s.
Nancy, her husband Charles and their three children lived in Australia for just a few years before returning to the US and settling in Arizona.
The family put down roots and as Savannah ascended to one of the most sought after roles in American television, her mother stayed in Tucson.
Nancy's disappearance has some peculiarities that set the case apart from what might be expected of a high-profile kidnapping in which the entire point is to get rich from ransom.
The two apparent ransom letters were sent to media outlets and were inconsistent in their requests. That immediately placed doubt over the letters and who sent them.
One was to a local news station, the other went to Los Angeles-based tabloid celebrity news outlet TMZ and reportedly included a demand for millions of dollars paid in Bitcoin.
The issue for investigators is there is no proof of life, and no specific information about how a kidnapper could be contacted.
"That makes it a very perplexing case in terms of how we can investigate it," Ms Schweit said.
During her time at the FBI, Ms Schweit investigated the case of an 88-year-old woman who was abducted from her home in the middle of the night. For 24 hours, there was no contact with the family but then the kidnappers reached out.
"We had a kidnapper who then contacted the grandson, and then contacted the father, and we had this back and forth communication … as this person sought to get what they wanted out of the deal, which was financial benefit," she said.
"We don't have that here."
Mr Alcazar agreed, saying the ransom notes were probably "a hoax".
"Because it was odd. You're demanding a ransom but it's only a one-way communication, so how are we supposed to get back to you, right?" he said.
"Unless they're dictating in the ransom 'deliver this money and deliver it in this account' and that's it. No-one's going to go for that. We have to verify proof of life, proof of custody, and that's why it was unusual.
"And I think that's why even Savannah perhaps doesn't believe those people had custody of Nancy. It was just another part of it that complicated this case."
In recent days, the FBI has said it was still investigating the legitimacy of the ransom notes, noting they referenced publicly available information about Nancy Guthrie. The FBI also announced it had made an arrest "related to an impostor ransom demand" associated with the case.
With no direct communication from apparent kidnappers, investigators go back to working the case, one piece of evidence and one tip-off at a time.
And unlocking the video from Nancy Guthrie's front door camera provided the "huge advance" the case was needing.
The masked person at the door
The black-and-white videos and photographs of a potentially armed person wearing gloves, a dark jacket, a backpack and a ski mask with holes for the eyes and mouth are grainy and disturbing.
They are also the only visuals authorities have released of a potential suspect in the disappearance.
The images taken by a doorbell camera next to Nancy's front door on the morning she went missing were posted earlier this week by FBI director Kash Patel and swiftly hailed as a breakthrough.
Sheriff Nanos initially cast doubt on whether authorities could obtain footage taken that night because the Nest camera was disabled around the same time Nancy went missing.
Mr Patel confirmed the photos, along with two videos, were recovered eight days later with the help of "private sector partners" from "residual data located in back-end systems".
In one of the videos, which goes for 29 seconds, the masked person, who appears to be carrying a gun, is seen approaching the front door, while another 14-second video shows the individual covering the door's camera with a plant the suspect took from the garden.
The FBI have since described the individual in the footage as a man approximately 5'9" — 5'10" (1.75 — 1.78 metres) tall, with an "average build", and identified the backpack he is carrying as a black, 24-liter Ozark Trail Hiker Pack in the hopes he or the item could be recognised by a member of the public.
"This is actually how we solve a lot of cases," Ms Schweit said.
She explained that she once worked a case involving a bank robbery that was solved because of the Red Ball Jet tennis shoes the suspect was wearing during the incident.
"There are so many clues available in those photographs and in the video footage, and … it will help lead investigators to the subject," Ms Schweit said.
As with other cases that have attracted media attention, Nancy's disappearance has gone viral on social media as internet sleuths try to solve the mystery with citizen detective work.
After the footage of the man at the door was released, online users were quick to home in on a moment in the video where the masked individual's right sleeve comes into view.
They speculated a marking in the small gap between the individual's latex glove and the sleeve could be a sign of a tattoo, which might help to rule potential suspects in or out.
While the tattoo theory has not been confirmed by authorities, the online discussion is another sign of the intense public fascination with the case and in America's desire to solve it.
"I think that's how they're going to solve this case, because somebody's going to give a tip," Mr Alcazar said.
"Somebody's going to identify this bad guy by his clothing, by his gait, by the way he walks, the way he carries himself, maybe with his wonky holster, the way he wears it.
"Someone's going to pick up on that and someone's going to identify him. So the job is for law enforcement to vet the information coming through."
Mr Alcazar said that was what happened in the search for Gabby Petito, a "van life" blogger who went missing in 2021 and was later found dead.
"[A] woman just happened to be filming and there goes the van and she didn't even know what she was filming. It's huge," he said.
The $US100,000 reward for information leading to Nancy Guthrie's recovery or the arrest of anyone involved in her disappearance, as well as digital billboards, which have been posted in major cities across the country, are other outward signs of the high-profile nature of the case and the public appeals for information.
And it appears they are working. Since February 1, the sheriff's department has fielded more than 18,000 calls about the disappearance, and more than 4,000 of those have come in since the front door camera video was released.
"It's great to have that many tips. We don't hesitate on that at all because the more you get, the more you see commonalities, the more every little piece of information can be put together for the puzzle," Ms Schweit said.
"This is a big puzzle. The more pieces you get, the better."
A huge amount of 'gumshoe detective work'
Investigators believe this was a premeditated crime by someone who knew who they were targeting.
The person that came to Nancy Guthrie's door tried to conceal their identity, armed themselves, and with blood spatters on the porch, Ms Schweit said there were obvious signs of "confrontation and struggle".
"I think this is an abduction that was intended and maybe it hasn't turned out the way the person thought it would," she said.
"But if the person did the surveillance, which I'm sure they did [because] this was a targeted abduction, the person … may know the medical condition of Ms Guthrie and may be providing some assistance."
Nancy's health has been a key concern since her disappearance because she requires daily medication and is said to have high blood pressure and heart issues, which is why she has a pacemaker. She also has limited mobility.
Ms Schweit said it was also a possibility the person responsible for the disappearance changed their mind, and "now they're in a different spot".
"They may just as easily have decided 'we just want to get away from it now' and they have abandoned her where she is or where she was, and they're just on the run," she said.
For investigators, this case has two parts: finding Nancy Guthrie and apprehending anyone responsible for her disappearance.
The experts the ABC spoke to believe it will be a combination of the immense public interest and classic investigative work that will solve it.
"Because the bottom line is that an individual who goes into somebody's house, takes that person and leaves, leaves behind a tremendous number of clues and it could be just a matter of a huge amount of gumshoe detective work where we will find our person," Ms Schweit said.
