A photo taken this week showed Mike Waltz using an app that looks like—but is not—Signal to communicate with top officials.

Former national security adviser Mike Waltz was photographed using a Signal-like messaging app during Wednesday’s Cabinet ...

Former national security adviser Mike Waltz was photographed using a Signal-like messaging app during Wednesday’s Cabinet ...

President Donald Trump's outgoing national security adviser Mike Waltz was photographed peaking at his phone under the table ...

Mike Waltz was photographed using Signal in a Cabinet meeting the day before Trump announced he was replacing him as national ...

Former national security adviser Mike Waltz was photographed using the Signal app during a Cabinet meeting on Wednesday, a ...

Waltz was at the center of the Signal chat controversy, in which a journalist was accidentally included in a discussion of ...

Waltz was among high-ranking members of the administration who accidentally shared plans about a forthcoming U.S. military ...

Mike Waltz, the national security adviser for President Donald Trump, is seen in photos using Signal during a Cabinet meeting ...

Waltz inadvertently added The Atlantic's editor-in-chief to a group thread discussing sensitive national security matters.

America has been bombing Yemen for two decades. That conflict ultimately led to Waltz’s dismissal as national security ...

White House national security adviser Mike Waltz is leaving the Trump administration just weeks after it was revealed he ...