The Obama administration’s prisoner swap with Iran involved freeing seven Iranians, dropping warrants on fourteen others, and paying Tehran $1.7 billion for five Americans. One of those, though, won’t be coming to the US. Nosratollah Khosravi-Roodsari has opted to stay within the hospitable confines of Iran despite the bargain. That might raise some eyebrows all on its own, but ABC’s John Parkinson reports that Khosravi-Roodsari’s presence in the deal raises even more basic questions — such as, who is he?

Khosravi-Roodsari’s name does not appear anywhere on the Internet prior to Saturday’s announcement when the State Department named him and four other Americans involved in the swap. In the digital age of the 21st century, his anonymity online is an anomaly in itself.

So what was Khosravi-Roodsari doing in Iran? How long had the American been jailed? Why was he imprisoned?

“When it comes to Roodsari, privacy considerations preclude us form offering any more details,” one senior administration official noted in an email to ABC News this morning. …

Given the exhaustive efforts the United States expended to win his freedom, Khosravi-Roodsari’s decision to stay in Iran rather than fly out with the others is also intriguing.

ABC’s earlier report on the deal never even mentions the mysterious hostage:

The first anyone had heard of Khosravi-Roodsari was when Barack Obama offered a terse mention of him in a prepared statement from the White House on Sunday:

Two other Americans unjustly detained by Iran have also been released — Nosratollah Khosravi-Roodsari and Matthew Trevithick, an Iranian — who was in Iran as a student. Their cases were largely unknown to the world. But when Americans are freed and reunited with their families, that’s something that we can all celebrate.

Trevithick’s case had been known, if not well-publicized, prior to his release. The Wall Street Journal can’t find anything on Khosravi-Roodsari even after the announcement, although State was a little more forthcoming with Felicia Schwartz:

Very little is known about Mr. Khosravi-Roodsari, whose family hadn’t come forward to speak about his release as of Sunday afternoon. It was unclear how long he was held in Iran or why he was arrested.

A State Department official said Mr. Khosravi-Roodsari was detained within the past year and the U.S. learned of his detention from Iranian authorities. “He is a U.S. citizen who was detained in Iran, and we were able to get him released,” the official said. “We have nothing further to add.”

Curious. Clearly, this isn’t someone who had a cover to blow; otherwise, the US government wouldn’t have let them stay behind. The mystery of Khorsavi-Roodsari may never get solved, especially since he appears willing to subject himself to arrest all over again rather than come home after the US bargained for his freedom. For his sake, here’s hoping he doesn’t need a second rescue, because the US probably won’t be much interested in providing one.

That time might come sooner rather than later. As soon as the hostages left Iranian air space, Obama slapped new sanctions on Iran for its ballistic-missile research:

Highlighting ongoing tensions between Washington and Tehran, however, the president announced new sanctions in response to two Iranian ballistic missile tests last year that violated international rules and sparked criticism of Obama’s approach to Iran at home.

The Treasury Department sanctioned 11 individuals and companies working to advance Iran’s ballistic missile program. The penalties were only announced after a plane carrying three of the Americans exited Iranian airspace on Sunday.

Perhaps the Iranians can comfort themselves from this massive slap with the $1,7 billion payment we made to the mullahs.