A man believed to be Sulaiman Abu Ghaith in a still from a 2002 video. (Reuters)

Sulaiman Abu Ghaith, Osama bin Laden's son-in-law and former spokesman, was captured overseas and brought to the United States today.

But if you haven't kept an eye on the CIA's most-wanted list, you may well be wondering who Abu Ghaith is -- or why Rep. Peter King (R-N.Y.) called his capture a "very significant victory" in the war on terror.

As the Posts' Greg Miller and Peter Finn report, Abu Ghaith would be, if tried, the closest relative of bin Laden to face trial in American court. The Kuwait native worked as a spokesman for his father-in-law, appearing in a number of al-Qaeda videos with and without bin Laden. He was one of three men to appear in a post-Sept. 11 video that celebrated the success of the attacks and warned there would be more strikes.

In the month after the attack, Abu Ghaith appeared on international television three times (read one translated transcript here) and published a fatwa in a Kuwaiti newspaper calling on Muslims to fight "Jews, Americans and all their allies," according to AP. That eventually led the Kuwaiti government to revoke his citizenship. Saudi Arabia's top religious leader was also forced to speak out against Abu Ghaith after he ordered Americans and Britons to leave the Arabian Peninsula before the land burned "with fire under their feet."

According to 2004 court testimony posted by AP, Abu Ghaith may have founded al Wafa, the "humanitarian organization" sanctioned by the United Nations Security Council for its ties to al-Qaeda.

Little has been published about Abu Ghaith's life before the Sept. 11 attacks. Born in Kuwait, he was "a quiet school teacher and mosque preacher," according to the AP. But the BBC put it differently in an October 2001 report:

Mr Abu Ghaith became famous in Kuwait during the Iraqi occupation, when he gave strong sermons, daring the government to attack Baghdad. He was banned from preaching in Kuwait after the country's liberation, because his sermons had turned against the government, the constitution and other Arab states.

In Afghanistan, Abu Ghaith married one of bin Laden's daughters. (He has at least 23 children.) According to the BBC report, Abu Ghaith had six children at that time and was 36, which would make him 47 or 48 years old now. A U.S. detainee who testified to working with him at al-Wafa called Abu Ghaith "a good person" who "honored his family."

The same detainee testified that he helped move Abu Ghaith's family to Pakistan shortly before the Sept. 11 attacks.

His whereabouts since Sept. 11 aren't clear, however. He is believed to have spent the last few years in Iran under "a form of house arrest." When he entered Turkey recently, he did so with a fake Saudi passport, according to the Turkish press. He was in the process of being deported to Kuwait when he was taken into U.S. custody in Jordan.

More details about Abu Ghaith would likely emerge during his trial, which is expected to be in New York. In the meantime, his capture is being trumpeted by some as a major win for the Obama administration.

"Definitely, one by one, we are getting the top echelons of al-Qaeda," King said. "I give the administration credit for this: it's steady and it's unrelenting and it's very successful."