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MIAMI (CBSMiami) – The case of missing Coral Springs resident and former FBI agent Bob Levinson’s took center stage at Tuesday’s White House press briefing.

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It was the focus of a series of questions about why Levinson was not included in the group of five Americans released in Iran over the weekend.

White House Press Secretary Josh Earnest told reporters why Levinson was not among those reunited with family.

“We have reason to believe that he is no longer in Iran,” Earnest said. “That’s why we continue to press for information about his whereabouts.”

Levinson’s son, Dan, told CBS4 News on Tuesday night however that the family believes the Iranian government can and should send him home.

“There’s no way that the Iranian government doesn’t know exactly what happened to him and where he is exactly right now,” Levinson said.

Levinson vanished in 2007 while working for the CIA. He was last seen on a small Iranian island.

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Several years ago his family received a video and photos of Levinson – showing he was being held. Since then, no more pictures. But the family says they believe he is still alive.

“The government officials that we’ve spoken with have told us that there’s no evidence that suggests he’s not alive,” Levinson said.

The White House said they are committed to bringing Levinson home and even made it part of the nuclear deal.

“One of the things that was secured in this specific agreement was a commitment from the Iranians to locate Mr. Levinson,” Earnest said.

But Levinson’s family of fears that with the nuclear deal completed and sanctions on Iran lifted, there is less leverage for the U.S. in pressing for Levinson’s release.

Dan Levinson hopes to soon meet with President Obama and Secretary of State John Kerry to determine their next steps in releasing his father.

“My dad is the only one really left there and he’s the one serving his country and the U.S. government cannot leave him behind,” Levinson said. “They cannot abandon him and we’re not gonna stop. We’re not gonna go away until he’s home with us.”

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Dan Levinson says the family has started a hashtag movement called #WhatAboutBob to keep pressure on to bring their father back home to his family in South Florida.