Saddam Hussein's son-in-law has left the Syrian capital, where he had been hiding, and surrendered to an Iraqi opposition group in Baghdad, an official from the Iraqi National Congress said Sunday.
Separately, the U.S. military said troops had detained Saddam's former minister of higher education and scientific research. The opposition said the official would be helpful in the search for signs of Iraq's nuclear weapons program.
Jamal Mustafa Abdullah Sultan al-Tikriti, who was deputy head of the Tribal Affairs Office in the ousted regime, is married to Saddam's youngest daughter, Hala. Iraq's pro-U.S. opposition leader, Ahmad Chalabi, told Fox News that he turned himself in.
One of Saddam's former bodyguards also surrendered to the opposition group. Both men could have information on the whereabouts of Saddam, said Haider Ahmed, a spokesman for the congress.
Sultan was being questioned Sunday by intelligence officers of the Free Iraqi Forces, the congress' armed wing, and would be turned over to the U.S. military "in a matter of hours, not days," said Ahmed.
Just hours after news of Sultan's surrender broke, U.S. Central Command said that U.S.-led forces captured Saddam Hussein's minister of higher education and scientific research.
Ahmed said Abd al-Ghafar is likely to know about Iraq's nuclear program. "We know about his background, and he is certainly involved with those banned programs," he said.
Al-Ghafar was ranked 43 on the U.S. military's 55 -card deck of Iraq's most wanted regime leaders. He is the "4 of Hearts" in the deck.
Sultan, in his mid-30s was ranked 40 on the list -- he is the "9 of Clubs."
Saddam's son-in-law apparently had been hiding in Damascus when he was urged to surrender.
"There have been some negotiations until he was persuaded to come to Baghdad and surrender to our people in Baghdad," said Ahmed.
Ahmed said he did not know precisely when Sultan surrendered, but believed it was Sunday. He said his information came "from my colleagues in Baghdad."
Ahmed said al-Tikriti was accompanied from Syria by Khalid Hmood, one of Saddam's top bodyguards, who also was arrested Sunday by the Iraqi National Congress.
Hmood was the head of Iraqi intelligence during the war and ranked a major in Saddam's personal security detail, according to Ahmed.
"I wouldn't be surprised if they have some information about Saddam's whereabouts or other officials," Ahmed said.
Officials at Central Command said they had heard the reports but could not confirm the surrender. Syrian officials were not available for comment. Congress officials had no information about the whereabouts of Saddam's daughter.
In August 1997, Saddam reportedly appointed Major General Kamal Mustafa al-Tikriti -- Sultan's brother -- in place of his second son, Qusai, as commander of the Special Republican Guard.
However, as of June 1998, General Kamal Mustafa was reportedly the director of the SRG Information Desk. General Kamal Mustafa is the most prominent professional officer in Saddam's immediate family. General Mustafa is married to the sister of Hussein Kamel, Saddam's son-in-law who was murdered on the dictator's orders when he returned to Iraq in 1996.
With the new captures, seven of the 54 wanted members of Saddam's inner circle are now in custody, though none of them are from the very top of the list. An eighth figure, Ali "Chemical Ali" Hassan al-Majid -- a top adviser to Saddam and the king of spades in the deck -- is believed to have been killed in an airstrike.
Saddam's former finance minister, Hikmat Mizban Ibrahim al-Azzawi, was arrested by Iraqi police in Baghdad and turned over to U.S. Marines on April 18. Al-Azzawi, who also served as a deputy prime minister, was the "eight of diamonds" in the deck of cards and the 45th most wanted.
Saddam's lead science adviser, Lt. Gen. Amer al-Saadi, turned himself in April 12.
On April 13, U.S. forces nabbed Saddam's half brother and personal adviser, Watban Ibrahim Hasan. Another half brother, Barzan Ibrahim Hasan, was arrested by U.S. Special Forces last Thursday.
Samir Abd al-Aziz al-Najim, the Baath Party Regional Command Chairman for east Baghdad, was handed over by Kurds near Mosul last Thursday.
Coalition forces are questioning them for information about Iraq's weapons programs, the whereabouts of other leaders and Iraqi links to terrorists.
U.S. officials are also tracking down thousands who enforced Saddam's control through assassination, torture and other misdeeds.
Catching these lower-level operatives -- and ultimately putting them on trial -- promises to be a massive and lengthy undertaking.
The administration wants to put these people on trial for alleged war crimes committed during this war as well as the 1991 Persian Gulf War. Cases also may be pursued for alleged atrocities committed over decades by Iraq's government against its citizens.
Human rights experts says Saddam had layers of security apparatus -- secret police, militias, intelligence agents -- all of whom committed widespread atrocities to quash political dissent and keep the Iraqi president firmly in control of the nation of 25 million.
Tens of thousands of people had such jobs. U.S. officials don't know how many survived the war or how many committed rights violations.
Coalition troops are sorting more than 7,000 prisoners captured from the battlefield, deciding who to release and who to hold for prosecution on war crimes or past rights violations.
"The whole fabric of society was corrupted by the violations all the way down to the local police officer who participated in the arrest of someone on political grounds," said Alistair Hodgett of Amnesty International USA.
"But the ultimate decision rests in the hands of the Iraqi people to decide how far down the line do the trials go," he said. "If you're a guy ... whose brother was taken away, imprisoned and tortured, it's not for the United States to say the (perpetrator) is a small fry."
The Associated Press contributed to this report.