The brother of US news presenter Savannah Guthrie has renewed his family's plea for proof that their mother is still alive after she disappeared last weekend.
As the first deadline from an alleged ransom letter passed, Camron Guthrie said in a video posted to Instagram that the family had not heard anything about their missing mother, Nancy Guthrie.
The 84-year-old is believed to have been abducted from her home in Tucson, Arizona in the middle of the night. Police launched a massive hunt, with officials offering a reward of $50,000 (£36,000) for information that leads to an arrest.
"We have to know that you have our mum," Camron said in the latest video message. "We want to talk to you."
"We haven't heard anything directly," he said in the video, posted on Thursday just after 17:00 local time in Arizona (00:00 GMT).
"We need you to reach out, and we need a way to communicate with you so we can move forward."
It came as the first supposed deadline for the Guthrie family to hand over money passed.
At a briefing on Thursday, FBI Special Agent Heith Janke said his agency was reviewing an alleged ransom note. It gave a deadline for payment of 17:00 on Thursday, he said, without specifying which time zone, and had a second deadline for Monday.
No further information was shared about what was threatened if the deadline was not met. "We're not going to go into specifics," Janke said.
It was announced the same day that authorities had made an arrest over a fake ransom note.
Earlier in the week, Savannah Guthrie shared an emotional video message, along with her siblings.
The host of NBC News' Today programme addressed the potential abductor or abductors directly, saying: "We are ready to talk... We need to know without a doubt that she is alive and you have her... Please, reach out to us".
The case has garnered nationwide attention, with dozens of reporters and camera crews descending on the quiet Arizona suburb where Nancy lives.
Pima County Sheriff Chris Nanos said on Thursday investigators were no closer to finding out who was responsible - but that they were working on the assumption she was still alive.
"Right now, we believe Nancy is still out there. We want her home," he said. "Everybody's still a suspect in our eyes."
Authorities have urged the public to call the sheriff's office with any information, vowing to look into all leads, and discouraging the spread of misinformation.
