Signal Sniffer Technology Used in Search for Missing Arizona Woman

Investigators are using a specialized tracking device to detect signals from Nancy Guthrie's pacemaker in hopes of finding her.

Feb. 20, 2026 at 4:15pm

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Authorities are using a 'signal sniffer' device mounted on a helicopter to try and locate Nancy Guthrie, an 84-year-old woman who went missing from her home in Tucson, Arizona. The device can detect signals emitted from electronic devices like Guthrie's pacemaker, which was disconnected from her phone at the time of her disappearance. Experts say the technology can extend the search range significantly, but building out the necessary infrastructure with drones will take time for law enforcement.

Why it matters

The use of 'signal sniffer' technology highlights the growing role of advanced tracking tools in missing persons cases, especially for individuals with medical devices that emit Bluetooth signals. However, the limitations of current capabilities, like the need for more drone infrastructure, show there is still work to be done to maximize the effectiveness of these new investigative methods.

The details

The signal sniffer device was mounted on a helicopter that flew slowly at low altitude over the search area, as the technology can pick up the Bluetooth signal from Guthrie's pacemaker which sends out a signal every 2-3 minutes. Experts say the range can be extended to several hundred feet with amplifiers and antennas, but a fleet of drones would be more efficient at covering a larger search radius. Law enforcement is still building out the necessary infrastructure to deploy signal sniffers on a wider scale.

  • Nancy Guthrie was reported missing on February 1 when she failed to show up for church.
  • Authorities say Guthrie's pacemaker was disconnected from her phone at 2:28 a.m. on the day she went missing.
  • The signal sniffer device was mounted on a helicopter that flew over the search area on Monday.

The players

Nancy Guthrie

An 84-year-old woman who went missing from her home in Tucson, Arizona in an apparent abduction.

David Kennedy

A former NSA hacker and inventor of the signal sniffer technology being used in the investigation.

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What they’re saying

“With amplification, with the ability to deploy things like drones or leveraging helicopters, they should be able to cover a lot larger area and then really home in just from a few meters to the actual signal itself.”

— David Kennedy, Former NSA Hacker (CBS News)

“You can really cut that time down pretty substantially across the board, you're probably talking, a day or a few days or a maximum of two weeks of being able to cover 120-foot-mile radius, to be able to actually identify it. It really comes down to manpower, drone operators [and] the drone technology itself.”

— David Kennedy, Former NSA Hacker (CBS News)

What’s next

The judge in the case will decide on Tuesday whether or not to allow Walker Reed Quinn out on bail.

The takeaway

This case highlights the growing role of advanced tracking technologies like signal sniffers in missing persons investigations, but also the limitations of current capabilities that will require more investment in infrastructure like drone fleets to maximize the effectiveness of these new investigative methods.