Authorities confirmed that at 4:12 a.m., a monitoring app linked to Nancy Guthrie’s implanted cardiac device recorded a three-minute transmission before going offline. Geolocation data placed the signal in a remote desert area outside Nogales.
Family members alerted law enforcement, prompting coordination between local deputies and the Federal Bureau of Investigation due to the cross-border proximity and medical telemetry concerns. By sunrise, agents searched the rugged site using GPS data and electronic detection equipment.
Nancy was not found, but investigators documented signs of recent activity, including tire impressions and scattered debris. Officials caution that cardiac devices can emit delayed or manipulated signals, and experts are now analyzing server logs and device data to determine whether the 4:12 a.m. alert reflected real-time presence, interference, or possible tampering. The investigation remains ongoing.