Amid the search for Nancy Guthrie, the mother of ‘Today’ show host Savannah Guthrie, NewsNation’s Brian Entin has reported that investigators are using a “signal sniffer” in an attempt to detect Nancy ...

Investigators searching for Nancy Guthrie reportedly used a helicopter-mounted "signal sniffer" to detect her pacemaker signal. What is it?

Authorities searching for Nancy Guthrie are deploying a piece of specialized tracking technology — commonly referred to as a “signal sniffer” — in an effort to detect emissions from her implanted ...