By Elizabeth Wolfe, CNN
(CNN) — As Nancy Guthrie’s family desperately pleads for her safe return, investigators announced Thursday they believe she is still alive – though they have no idea who may have taken her.
It has been five days since Guthrie, the 84-year-old mother of “Today” host Savannah Guthrie, was apparently kidnapped, disappearing from her remote Arizona home without her phone or critical medications.
Federal and local investigators have spent days working to recover video footage, analyze DNA and authenticate several potential ransom notes, but have so far received no “proof of life” or identified a suspect – even after Guthrie’s children shared a public appeal to possible captors.
The FBI on Thursday announced a $50,000 reward for information leading to Guthrie’s recovery or an arrest and conviction in her disappearance.
Here is what we know about how the apparent kidnapping and investigation have played out.
A Saturday evening supper
Nancy Guthrie was last seen by her family the evening before her disappearance, when she joined relatives for dinner and game night near her Tucson-area home.
Guthrie took an Uber to her daughter Annie’s home around 5:32 p.m. on Saturday, January 31, Nanos said. Detectives have since interviewed the Uber driver as part of the investigation, he added.
After dinner, family members dropped Guthrie back at her home, which lies in a secluded, cactus-dotted community in the Catalina Foothills.
Guthrie’s garage door opened at approximately 9:48 p.m. and closed at 9:50 p.m., the sheriff said.
“It is that time we assume that Nancy’s home and probably going to bed,” Nanos added.
A series of unusual overnight events
What happened in the late-night hours between Guthrie’s return home and her disappearance still remains shrouded in mystery. But a few small pieces of evidence may offer insight into when she may have been taken.
At 1:47 a.m. Sunday, a few hours after Guthrie is believed to have come home, her doorbell camera was disconnected, according to Nanos. Though he confirmed it was removed, he said “we’re not confirming that any cameras were smashed or destroyed around the house.”
About 25 minutes later, at 2:12 a.m., surveillance camera software detected movement, Nanos said. But in a crucial loss for investigators, the camera did not retain footage of the event. The camera owner did not have a subscription that would allow the software to save it, he said.
The sheriff initially said the camera detected a person, but later clarified it could have been an animal.
Guthrie’s pacemaker app data shows it disconnected from her phone at 2:28 a.m., Nanos said.
Guthrie’s cellphone was left behind at the home, a detail which may help narrow down the timeline for investigators, CNN Senior Law Enforcement Analyst Andrew McCabe said on “News Central” Wednesday.
“Likely, she was taken far enough away from (her phone) that the connection cut off. That could give us an indication of the moment she was taken from the home,” McCabe said.
It was not until later Sunday morning, after Guthrie was uncharacteristically absent from church, that a friend called her family to check in on her. When relatives checked on Guthrie at 11:56 a.m., they found she wasn’t home, authorities said.
Relativ