New York ( CNN ) -- The family of retired FBI agent Robert Levinson ca n't help but count the days since he vanished during a business trip to Iran 's Kish Island on March 8 , 2007 . Saturday marked 2,024 days since he 's been gone . `` Every day I miss him , '' said Christine Levinson , his wife of 38 years . `` I wake up and his side of the bed is empty . '' She left her Florida home this week to travel to New York in hopes of making a personal plea to Iranian President Mahmoud Ahmadinejad , who is attending this week 's U.N. General Assembly . Levinson is convinced Ahmadinejad can help in the search for her husband . `` In the past he has said that he will investigate and he will have his people investigate , '' Levinson told CNN . `` He has promised to help us . So we need to get him in touch with whoever can help us get the job done and get Bob home . '' Feds still hunting for missing FBI agent who vanished in Iran . The Levinson family says Robert was working as a private investigator looking into cigarette smuggling in Iran when he went missing . The State Department has repeatedly denied he was working for the government and has urged Tehran to find him . Last year , the Iranian government said it would make inquiries about Levinson but did not know what happened to him . Digital billboards were posted in Times Square this week with Levinson 's picture and a message to U.N. delegates asking for help in finding him . `` Because the U.N. General Assembly is here , we can get the world to help us , '' Christine Levinson said . The FBI has offered a $ 1 million reward for information leading to his safe return . His wife has also met with President Obama . `` He said that he would help any way that he could , '' and that `` he would put the full force of the U.S. government behind helping to get Bob home , '' she said . It 's believed Levinson , now 64 , is being held captive . U.S. officials believe he is somewhere in southwest Asia . It 's unclear who is holding him . `` There is every reason to believe based on all the evidence that Levinson is alive and well , '' a source with knowledge of the case said . The source would not provide further details . In a so-called `` proof of life '' video released last year but apparently made two years ago , Levinson appears about 50 to 60 pounds lighter . He stares and blinks as he looks into a camera and says he `` is not in very good health . '' He refers to 33 years of service to the U.S. government and asks the United States to `` answer the requests of the group '' that has been holding him . Who the group is and what they want is unknown . `` Please help me get home , '' Levinson says on the tape . Christine has sent several emails to the address where the proof-of-life video came from to ask the senders what they want . `` They have not responded . We have not heard back from them since then and that was almost two years ago . So it 's very difficult , '' she said . Levinson said she sees her husband 's determination every time she looks at that video . `` It gives me hope that I 'll see him again soon . And comfort that I can at least say to the picture , ' I love you . ' '' The Levinsons have seven children and two grandchildren . One daughter was married last year . Her brother stood in for their father and walked her down the aisle . Levinson has also missed a son and daughter 's high school and college graduations . `` They both wore yellow ribbons and carried pictures of Bob to the graduations just to keep him in our prayers , '' Christine Levinson said . She said she hopes to deliver this message to Iran 's leader : `` Please help my family to become whole again . We need Bob home as soon as possible . '' FBI offers $ 1 million for leads leading to safe return of missing retired agent . CNN 's Jill Dougherty contributed to this report .
David Levinson has been missing since 2007 . His wife says he was working as a private investigator in Iran when he disappeared . His wife hopes to ask Ahmadinejad personally for help . The Iranian government is the U.N. General Assembly .