Authorities are hoping Nancy Guthrie’s pacemaker may assist them in locating her exact whereabouts as the investigation into her disappearance reaches week three.

On Tuesday, February 17, the Pima County Sheriff’s Department offered an update on the case in which they revealed they’re using a relatively new technology to try to locate Savannah Guthrie’s 84-year-old mother’s pacemaker.

“Investigators are attempting to locate the device and are working with the manufacturer and other experts in the field to assist in that effort,” the Department said, per People.

They told CBS News they are using something called a “signal sniffer,” reportedly created by former NSA hacker David Kennedy. The strategy is said to be flying helicopters low to the ground so that it can bounce a signal that they hope will ping Nancy’s pacemaker and reveal her location.

Tracy Walder, a former CIA and FBI agent, told People that the technology is “somewhat experimental” and noted that the signal would need to hit “30 to 100 feet” from the pacemaker.

“So a helicopter has to hover low and slow in one particular area to look for it. I don’t think that’s practical. They need to know where they are looking,” Walder explained.

Investigators previously discussed the significance of the pacemaker shortly after Nancy’s February 1 disappearance, noting that it was disconnected from the monitoring app on her phone around 2:28 a.m. on the night in question. While it was previously ineffective at locating where Nancy is, it provided an important detail in the timeline of her kidnapping.

So far, one of the best leads that investigators have revealed to the public is a brief video of a masked man tampering with the doorbell camera at Nancy’s Arizona home. In an X post, the FBI described the person as “a male, approximately 5’9” – 5’10” tall, with an average build. In the video, the man is also wearing a black, 25-liter ‘Ozark Trail Hiker Pack’ backpack.