About
In February 2026, the FBI mounted a signal sniffer1 on a helicopter and flew low and slow over Tucson, Arizona, trying to detect Nancy Guthrie's pacemaker. The technology worked in principle. The problem was coverage. A helicopter can only be in one place at a time, and a pacemaker's BLE signal only reaches a few dozen feet. Meanwhile, thousands of people were going about their day, driving to work, stopping for coffee, hiking, running errands, within range of wherever Nancy was. They just didn't know to listen. BLEACORN makes every one of those people part of the search, without asking them to do anything differently.
The insight is simple: modern pacemakers and neurostimulators emit Bluetooth Low Energy signals every few minutes, around the clock, for the lifetime of the device (typically 10 to 15 years). These signals are detectable by any standard smartphone within range. An estimated 3,000+ missing persons cases per year in the U.S. involve someone carrying a BLE-enabled medical device.2
BLEACORN builds a passive, crowd-sourced detection network from those phones. When someone with the app passes within range of a target signal, the GPS coordinates are silently reported to authorities. The person with the app doesn't need to do anything, just live their life.
The name comes from Bluetooth Low Energy + Acorn -- the small thing that becomes something mighty. And it sounds like Beacon. Because that's what every phone with BLEACORN installed becomes: a beacon for humanity.
BLEACORN is a public safety initiative. There are no ads, no subscriptions, and no personal data is ever sold or shared. Detection reports contain only an anonymous identifier, GPS coordinates, and the matched signal, nothing that identifies the reporting phone's owner.
When a detection is made, location data is shared exclusively with verified law enforcement investigators. BLEACORN does not share location data with family members or case submitters. If law enforcement determines the individual left voluntarily and is not in danger, the case is closed and no location information is disclosed. BLEACORN respects every individual's right to privacy and safety.
1 A signal sniffer is a portable radio detection device that scans for Bluetooth Low Energy (BLE) transmissions. In the Nancy Guthrie case (Tucson, AZ, 2026), the FBI mounted one on a helicopter to sweep for her pacemaker's signal. A pacemaker's native BLE range is roughly 10-15 feet -- extendable to several hundred feet with amplifiers and high-gain antennas, but still limited by body tissue attenuation and physical terrain. Notably, the signal is weakest directly above and below the implant, and strongest at roughly the same horizontal plane -- the exact range where a passing pedestrian, driver, or shopper would be.
2 Estimate based on: approximately 61.2 million Americans age 65+ (U.S. Census Bureau, 2024); pacemaker prevalence of roughly 3 per 1,000 adults, rising sharply with age (NIH/PMC, 2025); over 3.5 million Americans living with implanted cardiac rhythm devices (U.S. Pacemakers Market Analysis, 2025); approximately 600,000 missing persons reports filed annually (FBI NCIC, 2024); and BLE-enabled pacemakers entering the market starting in 2018-2019 via Medtronic (BlueSync/Azure) and 2020 via Abbott (Gallant). Younger pacemaker recipients and neurostimulator patients increase the addressable population beyond the 65+ demographic alone.
Contact
For case submissions, use Submit a Case. For press inquiries or partnerships:
[email protected]