Follow CBSMIAMI.COM: Facebook | Twitter 

MIAMI (CBSMiami) — The son and wife of former FBI Agent and Florida native- still missing in Iran- spoke out following the release of three Americans over the weekend.

READ MORE: Fort Lauderdale Man Accused Of Sexually Assaulting Teen Girl

“We are happy for the other families. But once again, Bob Levinson has been left behind,” his family released in a statement.

Click here to watch a video of the interview. 

His wife, Christine Levinson and son Daniel Levinson spoke out Monday morning for the first time since the prisoners’ release.

“Actually I had to turn on the TV to find out what was going on which was really disappointing. I felt very betrayed and devastated that I hadn’t even received a phone call to let me know this was happening,” said Christine. “We had been promised that when the other people had been released Bob would be with him and he was not.”

CBS’s Charlie Rose asked “Betrayed by?”

“By the United States government,” said Christine.

“Do you know whether they asked for his release in this negotiation,” asked Rose.

READ MORE: Housing Crisis: County Mayors To Hold Roundtable On Skyrocketing Rents

“What I believe is they asked for his help, their help, to find him in order to get him home,” said Christine.

When asked if they were nervous about Bob possibly not being alive anymore, his son answered, “We obviously believe that he is still alive and the government has told us there is no credible evidence to suggest that he is not alive. So, of course, we’re going to go forward and we’re not going to give up.”

He went on to clarify, ” We believe the Iranians know where he is. They know exactly what happened to him.”

Related: Family Marks 8th Anniversary Of Disappearance Of Robert Levinson

Levinson disappeared from the Iranian resort of Kish Island more than 8 years ago while working as a consultant for the C.I.A. He is the longest-held american hostage. President Barack Obama has vowed the U.S. will work hard to free him.

On Monday, the FBI issued a statement on the mater saying:

“Today, the United States celebrates the safe return of four American citizens detained by the government of Iran to their families and loved ones. Unfortunately, the family of retired FBI agent Robert “Bob” Levinson still waits. Bob went missing from Kish Island, Iran in March 2007, and for almost nine years now, Bob’s wife, children, and grandchildren have waited for the release of their loved one. Bob forever remains part of the FBI family, and we remain committed to bringing him home safely to the family who misses him so much. The FBI expects our Iranian counterparts to fulfill their commitment to locate Bob and help bring him home safely.

In March 2015, the FBI increased the reward for information leading directly to the location and return of Robert Levinson to $5 million, and we continue to investigate and follow up on all information we receive, no matter how insignificant it might seem, to include all those received confidentially on and 1-800-CALL-FBI.”

MORE NEWS: 'Ride Of Silence' To Raise Awareness For Cyclists Safety On The Road