Nancy Guthrie’s abductor could be captured using crucial cell phone data — the same tactics law enforcement used in the Bryan Kohberger case, according to a forensic expert who analyzed the Idaho killer’s phone.
“You have to know what normal is to find evil, and this person’s phone would be considered the evil,” Heather Barnhart, an expert with Cellebrite and the SANS Institute who worked on the Kohberger case, told the Daily Mail.
Special agents from the FBI’s Cellular Analysis Survey Team (CAST) are busy methodically shuffling through batches of cell tower data from a wide area around Nancy’s Arizona home.
The team will carefully construct data profiles of normal phone activity versus abnormal phone activity in the hopes of spotting a potential outlier in the patterns — evidence that could help break the ongoing case.
Nancy, the 84-year-old mother of Today show host Savannah Guthrie was last seen Jan. 31. Her doorbell camera was disconnected between 1:47 a.m. and 2:28 a.m. the next day, when her pacemaker app dropped from her phone.
The Savannah, 54, has offered a $1 million reward to anyone with information about her mother’s whereabouts.
But a vital clue may already be stored in cell tower data, especially if the criminal turned their phone on or off — or made calls while in the vicinity of Nancy Guthrie’s home.
In the Kohberger case, Barnhart said, the killer entered 1122 King Rd. at 4 a.m. where he murdered Kaylee Goncalves and Madison Mogen, both 21, and Xana Kernodle and Ethan Chapin, both 20.
His phone was off between 2:47 am and 4:48 am.
“If you think about Bryan Kohberger, his device was turned off, so the tower right near King Road probably wouldn’t have picked that up at all,” explained Barnhart. “But when he left, he turned it on, because most people rely on their phones for navigation.”
The move “pings” nearby cell towers, and leaves behind the evidence in digital data files.
“Unless these people knew exactly where they were going, their phone will be off and then suddenly ping. So not just cell towers right by Nancy’s home, but take it a few miles out, spread out and look.”
The night of the abduction may not have been the only time the kidnapper was in the area. The digital experts will also analyze info recorded weeks before the horrific crime took place.
“If the person ever scoped out the house in advance, is there an unusual ping to towers? So, look at normal behavior. If we live in the same neighborhood, our phones are going to constantly ping that tower. Which ones are outliers?” said Bernhart.
Digital forensics can be monotonous and take a long time, Barnhart said.
“People, I think, want answers immediately, and I get it, but it’s hard to do digital forensics thoroughly,” she said. “And to me, they’re doing a thorough job, and that’s why it’s taking this long.”
While some criminals are wising up to how their cell phone activity affects the towers nearby, others don’t realize they’re leaving behind digital clues that could help law enforcement track them down.
“Bryan Kohberger not only powered his down, he turned off Wi-Fi, turned off cellular, and then powered it down like he was trying to completely get rid of his digital footprint,” said Barnhart.
But his cautionary tactics actually led to his downfall.
“In Idaho, that’s how we knew,” said Barnhart. “There is this gap of information where there are no pings from his device. It’s weird. Him powering off his phone gave us the perfect bookend of his crime, and really proved his intent to do harm to those kids in that house.”