Investigators in Nancy Guthrie’s disappearance are using a device called a “signal sniffer” to try to detect transmissions from her pacemaker. David Kennedy, former NSA hacker and inventor of the pacemaker signal detector, joins CBS News to discuss his work with law enforcement in the search.
https://www.cbsnews.com/video/pacemaker-signal-detectors-inventor-discusses-its-use-in-the-nancy-guthrie-search/