Nancy Guthrie's Kidnapping Timeline Detailed By Officials

Authorities in Tucson have revealed the timeline of the disappearance of Savannah Guthrie's mother, Nancy ... as a deadline looms in an alleged ransom plot.

According to authorities -- including Pima County Sheriff Chris Nanos -- Nancy left her own house at approximately 5:30 PM Saturday. After several hours of playing games and having dinner with loved ones, Nancy returned to her home.

Nancy got home around 9:48 PM, at which time the garage door opened. The garage door closed at 9:50 PM. The doorbell camera disconnected at approximately 1:47 AM. At 2:12 AM, the software for the camera detected a person ... and Nancy's pacemaker disconnected at 2:28 AM. No cameras around the property were smashed or destroyed.

Authorities acknowledged the alleged ransom note we obtained is the same one that local media outlets in the area received. FBI Agent Heith Janke revealed to reporters a ransom note "talked about an Apple watch, and one talked about a floodlight."

While they acknowledged some key pieces of information in the ransom letter, they wouldn't go into any detail about specifics because they don't want others trying to use more information to profit from the situation.

The FBI revealed further information about the letter we received ... including that the first deadline -- which changes the demands of the letter -- is at 5 PM today. The second deadline, which is more serious, is Monday, February 9.

Savannah pleaded yesterday for proof of life ... however, the letter indicates it would be the only communication regarding Nancy's disappearance.

Authorities also announced an imposter sent a bogus ransom demand, and that person has now been arrested.

The FBI announced at Thursday's news conference there is now a $50K reward for information leading to the return of Nancy. FBI Director Kash Patel is being briefed several times a day on the situation.

The sheriff confirmed there was in fact blood by the front door ... as evidenced in video taken by NewsNation reporter Brian Entin. However, they wouldn't confirm there was forced entry despite previous reports.

Nanos says he and his fellow law enforcement officers still believe Nancy is alive out there ... and, they're doing everything they can to find her. They're even reaching out to pharmacies and hospitals to check their logs -- because Nancy requires specific medications to keep her alive.

Nanos reiterates they have not identified suspects or persons of interest in the case at this time.

As you know ... Nancy was last seen late Saturday night -- and a family member reported her missing Sunday morning. When cops arrived at her Tucson, Arizona home, they say they observed concerning signs at the scene.

Video taken at the home after the break-in captured what appeared to be a trail of blood just outside the front door of the residence.

TMZ received an alleged ransom note earlier this week, which we passed on to law enforcement ... and Savannah Guthrie responded via video to an alleged demand letter -- calling for proof of life from alleged abductors before talks could move forward.

Tons of rumors about the case are floating around ... including former NewsNation journalist Ashleigh Banfield reporting Tommaso Cioni -- Nancy's son-in-law -- is a suspect. The Pima County sheriff shot down the report and told us they have not identified a suspect yet.

Investigators searched Tommaso and Annie Guthrie's home thoroughly Wednesday ... with an Internet Crimes Against Children investigator entering the home.