Savannah Guthrie latest: Police believe missing mother of TV presenter 'still out there'

Heith Janke says an imposter was arrested "earlier this morning", but the FBI does not believe it has any connection to Nancy Guthrie's case.

"It was someone that was trying to profit from it," he adds.

"A total imposter." 

Janke also speaks directly to anyone involved in Guthrie's disappearance: "Do the right thing."

"This is an 84-year-old grandma that needs vital medication for her well-being. You still have the time to do the right thing before this becomes a much worse scenario for you. Please return Nancy home," he adds.

Heith Janke, FBI special agent in charge, says the bureau is aware of a "ransom letter that was sent to the local media and then to national outlets".

He adds that the FBI is taking it seriously and there is communication with Nancy Guthrie's family.

"We advise and recommend from a law enforcement perspective, any action taken on any ransom is ultimately decided by the family," Janke says.

Sheriff Chris Nanos says the office cannot confirm whether "any cameras were smashed or destroyed" around the house.

"I don't know where that came from," he says.

"That's something we're not confirming." 

Sheriff Chris Nanos also addresses rumours that there had been signs of forced entry at Nancy Guthrie's residence.

"I have no clue where that comes from," he says. 

"We have been very consistent: we are not discussing that at all.

"Whether it's forced entry or not forced entry, that is something we're just not discussing."

Sheriff Chris Nanos has detailed the timeline around Nancy Guthrie's disappearance.

Here's a rundown of what he says:

• Saturday, 5.32pm: Nancy travels to her family's home for dinner and to play games;
• Saturday, 9.48pm: Nancy was dropped off at home. Nanos says "at that time we assume Nancy's home";
• Sunday, 1.47am: Nanos says the doorbell camera disconnects and at 2.12am software detects a person on camrea, but there's no video available. Nanos adds that it could potentially be an animal, "I imagine that's possible";
• Sunday, 2.28am: Nancy's pacemaker app shows that it was disconnected from her phone;
• Sunday, 12.03pm: 911 is called in to the Pima County Sheriff's Department;
• 12 minutes later, Nanos says "our patrol team arrives"

The FBI says it's now working the case jointly with Pima County Sheriff's Department.

Heith Janke says the FBI is offering a $50,000 (£37,000) reward for information leading to the recovery of Nancy Guthrie and or the arrest and conviction of anyone involved in her disappearance. 

"The FBI has agents, analysts and professional staff employees working day and night with our partners at the sheriff’s department," Janke says.

"We have deployed additional intelligence and agents from our Phoenix office."

Sheriff Chris Nanos says police have not yet identified a suspect in the kidnapping case.

"We are working our best to do that," he says. 

"But to be clear, we have nobody of interest or any suspects that you would consider a prime suspect," he adds.

The force are "just not there yet", Nanos says.

Sheriff Chris Nanos says blood found on the porch of the 84-year-old's home "came back to Nancy".

"There's still more items that have been submitted," he adds.

"We just haven't got them back yet." 

Nanos says there are several leads "coming in" and police will be working quickly to get an answer. 

Sheriff Chris Nanos is now speaking at the news conference.

He says the family of Nancy Guthrie are "hurt" and that police believe she is "still out there".

"Right now, we believe Nancy is still out there. 

"We want her home. Our department, the sheriff's department, along with all of our partners at the FBI, have been working around the clock.

"We just want her home and get and find a way to get to the bottom of all of this, just as you do."

Pima County Sheriff's Department has started its news conference to give an update on the investigation into the search for NBC anchor Savannah Guthrie's 84-year-old mother, Nancy.

Watch live at the top of this page. We'll also be providing text updates here in the blog.