EXCLUSIVE: American Prisoner in Iran Taunted After Obama's White House Correspondents' Dinner Speech

Family of American veteran held by Iran fears he is no longer a U.S. priority.

— -- Just hours after President Obama used his appearance at the White House Correspondents' Dinner to call for the release of an American journalist held prisoner in Iran, another American held at the same prison was taunted by Iranian prison guards who told him the president did not mention his name, his family said.

“He has already been mistreated, abused, and tortured,” writes Sarah Hekmati, Amir’s sister, in a letter to White House counter-terrorism advisor Lisa Monaco. “Now the mental torture continues as he is made to feel that the country he put his life on the line for, the one he defended, and the president he voted for has left him behind and are not actively trying to secure his freedom.”

Of the three Americans known to be imprisoned in Iran, Hekmati has been held the longest. He was arrested in 2011 when, according to his family, he was visiting his ailing grandmother in Iran. He was sentenced to death in January 2012 for “espionage, waging war against god and corrupting the earth.”

“Why has President Obama yet to utter the name Amir Hekmati?” his sister wrote. “Why on days significant for Amir -- Memorial Day, Veteran's Day, the anniversary of his death sentence, the anniversary of his imprisonment -- President Obama cannot say the name Amir Hekmati out loud, but he can say it for Jason Rezaian and he can say it for Pastor Abedini? Why when we make a request is it ignored? Why am I forced to write this email to you AGAIN, the same subject AGAIN, the same plea AGAIN?”

ABC News posed her questions to the White House today and was told by Press Secretary Josh Earnest that “each case and the efforts that we're undertaking to secure their release is treated independently.”

“Certainly when considering how best to secure the release of these individuals, a calculation is made about the wisdom of the publicity that surrounds the efforts to secure their release,” Earnest said.

“The concern for the well-being of those individuals is shared by everybody here at the White House. We've made clear what those concerns are to the Iranian government. And we're going to continue the effort to try to secure the release and safe return of these individuals,” Earnest said.

Meanwhile, the Hekmati family waits for answers.

“Please spare us this dignity and give us a straightforward answer as to why in nearly 4 years President Obama has [not] raised Amir’s plight individually outside of the context of the others imprisoned. Not even once. Not even when he was sentenced to death. The only question at this point is why,” Sarah Hekmati wrote.