Soon after the release of five American prisoners in an exchange of hostages with Iran, the family of former FBI agent Robert Levinson felt "extremely betrayed" by the White House. "We are happy for the other families. But once again, Bob Levinson has been left behind," read a statement by the family, reported Reuters.

Levinson disappeared March 9, 2007, while on an unauthorized intelligence gathering mission with the CIA. He was last seen on Kish Island, off Iran's coast.

"We had to learn it from the TV ourselves, and that's very disappointing and heartbreaking," said Levinson's wife Christine, according to Fox News.

State Department spokesman John Kirby said the government had planned to inform the Levinsons about the release of the Americans before the news broke.

"The Iranians leaked the information early, too early for us to have made the phone calls and notifications that we wanted to make. Believe me, nobody is happy about the way that went down," said Kirby, reported NBC News.

"The people who are working on the case directly, they have told us there is no evidence to suggest my dad is not alive. We're not going to give up because, obviously, we're doing everything we can. We need to make sure his country is doing the same," said Levinson's son Dan, according to Fox News.

But when asked by reporters during a press conference if Levinson was still alive, Secretary of State John Kerry said, "We have no idea," reported Fox News.