By bizn_fun 
There has been a lot of movement in the case of the disappearance of Nancy Guthrie, the mother of US TV host Savannah Guthrie, over the past 24 hours.
In Arizona, where the case is playing out, it’s now just past 4am, so we’re not expecting many updates to come in for the moment but we’ll keep you posted as they do.
In the meantime, here are the main things you need to know about the latest events:
What do we know about the disappearance?
The NBC News anchor’s mother was last seen at roughly 9.30pm on 31 January, when she was dropped off at home by family after having dinner with them, the sheriff’s department said.
Guthrie, who lives alone, was then reported missing by her family the next day, Sunday, after she did not attend church.
Watch Savannah Guthrie’s latest plea for “help”:
Why is there so much urgency about the search?
Guthrie has a pacemaker and needs daily medication, and her family and authorities have said they are concerned her health could be deteriorating by the day.
What have been the demands in the ransom notes?
At least three media organisations reported receiving apparent ransom notes during the week after Guthrie’s disappearance, which they handed over to the police.
Heith Janke, the FBI chief in Phoenix, said details in the messages to news organisations included a demand for money, with a deadline for last Thursday evening and a second deadline for Monday if the first one was not met.
What new insights do investigators have?
Yesterday, the FBI released new photos of an “armed individual” from a recording device that appears to be a doorbell camera.
Watch: ‘Armed individual’ seen outside Guthrie home
A man was detained during a traffic stop and questioned by authorities in relation to the case, the local sheriff’s office said yesterday.
He was reportedly released again, with delivery company DoorDash investigating if the man was one of their drivers.
The Pima County Sheriff’s Department and the FBI also conducted a search of a location in Rio Rico, Arizona, about 60 miles south of Tucson, where the Guthrie home is.
What has Savannah Guthrie said?
In a social media post after the new images were released, Savannah Guthrie said: “We believe she is still alive. Bring her home.”
She also pleaded to anyone with information to contact law enforcement.
Last week, she told her mother’s captor the family was “ready to talk” and would pay for her return.
But she added that they needed to know “without a doubt” that she was alive and held by the alleged kidnapper.