"Whoever is out there holding our mother, we want to hear from you," said Camron Guthrie said in a video shared on Savannah's Instagram account. "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."

"We have to know that you have our mom," he continued.

"We want to talk to you, and we are waiting for contact," Camron concluded.

No suspect or person of interest has been identified in the case, according to Pima County Sheriff Chris Nanos, who said "we believe Nancy is still out there" during a press briefing on Thursday (February 5) via ABC News. The FBI is now jointly investigating the case with local Arizona officials and offering a $50,000 reward for information leading to Nancy's recovery or the arrest and conviction of anyone involved in her disappearance.

A ransom note sent to TMZ claims that Nancy is "safe but scared" and aware of the demands made for her return, the outlet's founder Harvey Levin told FOX News' Sean Hannity Thursday night.

“I will say the letter begins by saying she is safe but scared, and they go on to say she knows exactly what the demand is," Levin said of the note, which demanded millions in bitcoin in order for "consequential" repercussions to be avoided.

“They are, through us, telling the family exactly what they are demanding, and they are saying that Nancy is aware of it,” he added. “They are also saying… that this will be their only communication and they are done communicating and negotiating —here’s the deal and that’s it.”

“As the clock ticks, that’s one of the reasons the FBI and other authorities have gotten desperate here,” Levin added.

A California man was identified as the man charged after sending separate phony ransom texts to Guthrie's family regarding her missing 84-year-old mother Nancy, according to a criminal complaint filed Thursday, FOX News' Michael Ruiz reports. Derrick Callela messaged Nancy's daughter, Annie, and her husband, Tommaso Cioni with false information about the missing woman's whereabouts.

“Did you get the bitcoin were [sic] waiting on our end for the transaction,” Callela allegedly wrote to the couple.

Data obtained by authorities approximately three minutes later showed Callela also made a nine-second-long call to an unidentified member of the Guthrie family.

The arrest was made prior to authorities confirming that Nancy was still believed to be missing and hours after Savannah and her siblings made an earlier plea for their mother to be returned safely.

“We need to know, without a doubt, that she is alive, and that you have her. We want to hear from you, and we are ready to listen. Please, reach out to us,“ Savannah said, along with her two siblings.