A deadline to pay $6 million in bitcoin demanded by the alleged kidnappers of Nancy Guthrie has passed — and federal authorities say they are “not aware” of any contact between the family and unidentified suspects.

PEOPLE previously reported, citing sources with knowledge of the situation, that a ransom note sent to local Arizona television stations KOLD and KGUN, along with TMZ, specified two separate sums the family must pay: $4 million in bitcoin due Thursday, Feb. 5, and, if that was not met, an increased demand of $6 million by Monday, Feb. 9.

Thursday’s deadline passed without a payment being made, giving the family until 5 p.m. local time Monday to make the $6 million payment, according to the sources.

It is unclear if this deadline was met as the FBI did not disclose that information in a statement provided to PEOPLE just after 5 p.m. Monday.

“The FBI is not aware of any continued communication between the Guthrie family and suspected kidnappers,” said FBI Phoenix Spokesperson Connor Hagan, per the statement.

This comes amid a massive investigation into Nancy’s disappearance, who was last seen at her home in Tucson on the night of Saturday, Jan. 31 after being dropped off by family following a dinner.

The 84-year-old mother of Today co-host Savannah Guthrie failed to show up for church the next day, and Pima County Sheriff Chris Nanos announced at a press conference on Tuesday, Feb. 3, that they believe Nancy was taken against her will.

Nanos later confirmed that blood found on the exterior porch of Nancy’s home matches her DNA.

However, no suspects or persons of interest had been identified in Nancy’s kidnapping as of Sunday, Feb. 8, the Pima County Sheriff’s Department shared on social media.

This remained the case on Monday, with Hagan confirming to PEOPLE that authorities have still not identified a suspect or person of interest at this time.

“For more than a week, FBI agents, analysts, and professional staff have worked around the clock to reunite Nancy Guthrie with her family,” Hagan said. “Additional personnel from FBI field offices across the nation continue to deploy to Tucson. We are currently operating a 24-hour command post that includes crisis management experts, analytic support, and investigative teams. But we still need the public’s help.”

The FBI is now offering a $50,000 reward for any information leading to Nancy’s recovery or an arrest in the case.

Anyone with tips or leads is asked to call 1-800-CALL-FBI in addition to the Pima County Sheriff’s Department at 520-351-4900.

Heith Janke, the special agent in charge of the FBI’s Phoenix division, previously addressed alleged ransom notes during a press conference on Thursday, Feb. 5. He declined to provide further details, apart from confirming the requested deadlines of Thursday, Feb. 5 and Monday, Feb. 9.

Janke also referenced an Apple Watch and floodlight during that press conference.

On Friday, Feb. 6, the FBI acknowledged a new message potentially tied to Nancy’s kidnapping. “Investigators are actively inspecting the information provided in the message for its authenticity,” the statement read.

This came after a person was arrested for sending a fake ransom note the day before, Janke said.

Janke urged members of the public to avoid taking advantage of the situation, noting that “imposters” will be prosecuted.

“We will investigate and ensure you are held accountable for your actions,” he said.