“We need to keep their confidence, so that we can keep working well together as a team,” Ms. Tice told Mr. Lauer.

The Trump administration began searching early this year for ways to free Mr. Tice, even setting up a back channel with Syria.

Image Austin Tice in an undated photo. Credit... Family of Austin Tice, via Associated Press

“We are absolutely gratified at the engagement we’ve had with this new administration,” Ms. Tice told Mr. Holt. “How quickly they’ve become aware and engaged and advocating for Austin’s safe return.”

The Syrian government insists it does not know what happened to Mr. Tice or where he is. And his parents said that they had seen no proof that he was alive, they told Mr. Holt, aside from a YouTube video that was posted one month after Mr. Tice disappeared.