On Tuesday, my father, Robert Levinson, became the longest-held hostage in U.S. history. Sadly, his 6 years 8 months in captivity surpasses the 2,454 days that Terry Anderson, the former Associated Press bureau chief in Beirut, was held from his family.

My father was last seen March 9, 2007, on Kish Island, Iran, but he is not a missing person. Our family received a hostage video three years ago and photographs in 2011. In the video — in which he appears frail and visibly thinner than the 100 kg he weighed when he was taken — my dad pleads for the U.S. government to help secure his release. In the photos he is shackled. He has an unkempt beard and holds cryptic messages, the intended meaning of which we still do not understand.

What we do understand is that the Iranian government takes great pride in its security efforts. We respectfully request that the Rouhani administration help us find my father.