When four Americans were released from Iran last week as part of a prisoner exchange, Robert Levinson, a retired FBI agent and contractor for the CIA, was notably not among them. Levinson was kidnapped while working in Iran in 2007, and after appearing three years later in a video and then a series of photos made by his captors, he hasn’t been heard from since.

Unusually, the Obama administration made no public statements last week calling on Iran also to free Levinson, and there’s at least one reason for that: Senior officials in the U.S. intelligence community and the administration believe that Iran doesn’t actually know where Levinson is, current and former officials with knowledge of his case told The Daily Beast.

“I think it’s nearly certain that they don’t know where he is,” one former official said, speaking on condition of anonymity because the U.S. is still working with Iran to find out what happened to Levinson.

They aren’t relying merely on the word of Iranian officials, who’ve said for years they don’t have information on Levinson’s whereabouts or who took him. Intelligence that the U.S. has collected on Iran and government officials has helped to persuade some who’ve been working to find Levinson that Tehran has lost his trail—if it ever had it.

The conclusion among senior officials that Iran doesn’t know how to find Levinson helps to explain why he wasn’t part of the recent swap that ended with four Americans, including Washington Post journalist Jason Rezaian, being freed.

For years, competing theories about what happened to Levinson have only deepened the mystery surrounding his case. Some have speculated he was kidnapped by organized criminals while working on a private investigation on Iran’s Kish Island, or that he was taken by a rogue faction in the Iranian security services, or in the country’s Revolutionary Guard Corps, which operates with considerable autonomy.

The fact that some U.S. officials now believe that the central government doesn’t know where Levinson is may bolster those theories.

Brett McGurk, a top U.S. diplomat who worked on the prisoners’ release, told CNN that if the U.S. “knew Bob Levinson was in a prison cell in Iran, I think you know we’d have a different outcome here.”

“In fact, it appears that he’s not being held in Iran,” McGurk added, echoing statements from top administration officials over the years, including former Secretary of State Hillary Clinton, that Levinson was moved out of the country years ago. In 2011, Clinton said publicly that recent information indicated Levinson was being held “somewhere in southwest Asia.”

In an interview last Sunday with CBS’s Face the Nation, Clinton seemed to put herself in the camp with those who think Levinson is either dead or beyond Tehran’s reach.

“I regret deeply that Robert Levinson was not on his way home either,” Clinton told host John Dickerson, who asked if she thought “the Iranians know where he is.”

“And I hope and expect that the Iranians will continue to be pressed very, very hard to give up any information they have and, if possible, to return Bob Levinson to his home and family,” she added.

The phrase “if possible” was telling on a few levels. First, it implied that the Iranian government might not be able to say where Levinson is. It also suggested that he may no longer be alive.

U.S. officials have said they never stopped trying to find Levinson. More than a year ago, the Obama administration opened a separate channel of discussion with Iran devoted exclusively to repatriating Americans, which ended in the prisoner swap. Levinson’s status “was also central to these discussions,” a senior administration official told reporters on Sunday.

“We’ve also agreed to continue a dialogue with Iran through multiple channels for missing persons, in particular for Bob Levinson,” the official added. “And we made some progress in that case, but that’s a case that we are never going to quit and never going to give up on, and he’s central to our minds every single day. And we’re going to continue to do everything we possibly can to find Bob and bring him home.”

But Levinson’s son, speaking on behalf of the missing American’s family, rejected the notion that Iranian officials couldn’t locate his father and said he feared the captive was already being forgotten.

“I think it’s absolutely ridiculous to think that the Iranians don’t know,” Dan Levinson told The Daily Beast. “He was picked up by the Iranian security forces and the Iranian state media reported that… There are people in the Iranian government who know exactly where my dad is.”

And there are people within the U.S. government who believe that, too. They tend to work in the FBI, where Levinson was once an agent, the current and former officials said.

CNN reported on Wednesday that FBI investigators believe Levinson, if he is alive, is still being held in Iran.

Levinson’s son said he thought it was plausible that top leaders in the Iranian government, including Foreign Minister Javad Zarif and President Hassan Rouhani, don’t know how to find Levinson.

“It might be other people in rogue factions of the Iranian government that actually have him,” the younger Levinson said. But he insisted that the Obama administration “needs to press harder to speak to those people,” and to anyone else who might have information on his father. Levinson said he worried that if many officials conclude there’s no real hope of finding his dad, the momentum to finally bring him home will stall, and he’ll be forgotten.

Levinson said his family already felt neglected. They only found out that U.S. hostages had been freed from watching news reports. Levinson said Secretary of State John Kerry had spoken to his mother last Tuesday, just a few days before the swap, but he gave no hint of any imminent release.

When the family heard the news, they immediately began calling their contacts in the administration, demanding to know why Levinson wasn’t among those returning to the U.S.

“You left him behind again!! My family is in tears,” Levinson’s mother wrote to one administration official in an email that her son read to The Daily Beast.

Levinson said he wants the administration to use that new channel that proved so successful in freeing the four other Americans to help his father.

“Everybody’s won. The only people who are suffering now are my family,” Levinson said. “We’re the ones who are just left behind. We’re the forgotten ones.”