The "signal sniffer" being used in the Nancy Guthrie investigation was mounted on a helicopter on Monday.

The messaging app Signal is making headlines again, with the news that U.S. Defense Secretary Pete Hegseth used it for a chat with his wife, his personal lawyer and others in which he shared sensitive ...

Mike Waltz, the departing national security adviser at the center of "Signalgate," is seen in new photos using the commercial messaging application during a Cabinet meeting held by President Donald ...

The nation’s top intelligence officials have told lawmakers that it was routine for them to discuss sensitive national security issues on the encrypted messaging app Signal. It’s widely used at their ...

Former national security adviser Mike Waltz was photographed using a Signal-like messaging app during Wednesday’s Cabinet meeting, more than a month after he first came under intense scrutiny for ...

Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The First Church of Christ, Scientist, and we’ve always been transparent about that. The church publishes the ...

A photo taken by Reuters' Evelyn Hockstein during a Cabinet meeting Wednesday shows Waltz holding his phone below the table, with the encrypted-texting app open and visible. It also shows Waltz in ...