Members of the political organization headed by Ahmed Chalabi are suspected of providing information to Iran on U.S. troop positions in Iraq and of kidnapping a prominent physician from his home, according to U.S. and Iraqi officials familiar with three investigations into a group the Bush administration once favored to run postwar Iraq.

On Thursday, Iraqi police, backed by U.S. soldiers, raided Chalabi's home and the offices of the Iraqi National Congress, a coalition of parties that opposed the government of Saddam Hussein. Until recently, the group received $335,000 a month from the Pentagon for help in gathering prewar intelligence about Hussein's government and in finding his top lieutenants after the invasion.

Chalabi, a longtime exile leader who was once the Pentagon's preferred choice to be Iraq's postwar leader, characterized the raids as retaliation for his criticism of U.S. policy in Iraq.

Iraq's U.S.-appointed Governing Council, of which Chalabi is a member, met Friday in an emergency session to discuss how to respond to the raid, which many of its members linked to U.S. occupation officials.

In interviews Friday, INC members, senior officers of the Iraqi police force and U.S. officials outlined three distinct investigations into the INC, which in addition to Defense Department funding received $33 million from the State Department over the past four years.

The inquiries are focusing on allegations of corruption, kidnapping and robbery, and on a U.S. suspicion that one of Chalabi's closest advisers is a paid agent of the Iranian intelligence service, according to U.S., INC and Iraqi police officials. The adviser, Aras Habib, has a long working relationship with the Defense Intelligence Agency and is now a fugitive.

Chalabi is not wanted for arrest.

One of Chalabi's advisers said Friday that INC officials received advance notice of U.S. plans to search the INC intelligence building and removed their computers weeks ago. The adviser, Francis Brooke, said "nothing of any intelligence value" was recovered in the raids.

With the United States preparing to transfer limited power to an interim Iraqi government in a little more than a month, the move against the INC has been portrayed by Chalabi as a U.S. effort to isolate him before the new government is named.

The Bush administration once regarded Chalabi, a moderate Shiite Muslim businessman who spent decades in exile, as a leading candidate to be Iraq's leader after Hussein was toppled. But over a difficult year of U.S. occupation, Chalabi has accused U.S. officials of failing to move quickly enough to transfer power and has criticized U.N. involvement in the process.

At a hearing on Capitol Hill, some Democratic members of the House Armed Services Committee expressed puzzlement over the latest turn of events regarding Chalabi.

"We support our troops, and we support you gentlemen -- it's your civilian bosses in the Pentagon I'm increasingly worried about," Rep. Jim Cooper (D-Tenn.) said to Air Force Gen. Richard B. Myers, the chairman of the Joint Chiefs of Staff, and two other senior officers testifying before the panel. "This seems to be a substantial development in the war, when one of the most highly paid and trusted advisers may have deliberately misled our nation for months and years and some of our officials may have swallowed it hook, line and sinker."

Myers said he knew very little about Chalabi, despite the Iraqi's close relationship with the Pentagon.

"If this man was on the U.S. payroll until last week, what has changed in the last few days to make him the subject of a raid of this type?" Cooper asked.

"That I can't tell you," Myers responded. "What I can tell you is that the organization that he is associated with has provided intelligence to our intelligence unit there in Baghdad that has saved soldiers' lives."

Myers was pressed again on the issue by Rep. Timothy J. Ryan (D-Ohio), who asked, "Have we been duped by a con man?"

"I don't have the information that can allow me to make that judgment," Myers said. "I think that remains to be seen, probably. But I just don't know."

Sometime in the past few weeks, L. Paul Bremer, the U.S. civilian administrator of Iraq, referred the results of an Iraqi police investigation of the INC to the U.S.-created Central Criminal Court of Iraq. An Iraqi judge outlined charges Thursday that included kidnapping and torture, fraud and "associated matters."

"Ambassador Bremer doesn't intervene in these respective cases, he just handles the procedural matter of referring it," said Daniel Senor, Bremer's spokesman.

A senior Iraqi police officer involved in the case said most of the eight suspects the police sought Thursday were involved in an armed robbery and kidnapping last month that was allegedly carried out by INC members.

The officer, who declined to be named for fear of losing his job, said his office had received complaints for months about INC members impersonating police officers, breaking into homes and carrying out robberies. He said police officers had warned the INC offices several times about the allegations. In the past three weeks, he said, police have arrested four INC officials on robbery charges.

"They knew all about this," the officer said. "It was not the first time."

In April, a respected cardiologist from Baghdad Medical City filed a criminal complaint alleging that he was kidnapped by men he identified as INC members.

The men visited his home one night, accused him of harboring terrorists and asked to search his house, according to the officer who took the complaint. They stole $20,000 in cash and a computer, then they took him away in an SUV, the officer said.

The doctor said he was hooded and driven to a building where he was interrogated, according to the officer. When the men removed the hood, the doctor said, he recognized four of them as INC members. The men were among the eight suspects whom police officers were seeking Thursday.

The officer, who participated in the raid at Chalabi's house, said Chalabi challenged them politely at his door.

"He asked, 'Why are you guys working with the Americans? You are the major crimes unit?' " the officer recalled. "I said, 'We aren't. We're the police. We have a warrant and we are executing it.' "

Brooke, the INC adviser, said the raids were likely related in part to the investigation of Sabah Nouri, a German national whom Chalabi picked to be the Iraqi Finance Ministry's anti-corruption officer. Nouri was arrested in April after auditors discovered a $22 million shortfall in the program overseeing Iraq's transition to a new currency this year. Brooke called him "a low-level" INC official.

Brooke said Habib, the INC's longtime intelligence chief, was the primary target of the investigation. A U.S. official in Washington said Habib was being investigated on suspicion of being a paid agent of the Iranian intelligence service and that the allegations stemmed from current activity with foreign governments.

According to Brooke, a former subcontractor on a CIA program in northern Iraq who has a 10-year association with Chalabi, Habib had been at odds with the CIA for a decade. When a CIA officer asked Habib in the mid-1990s to use an INC intelligence network in northern Iraq to gather intelligence against Iran, Habib "told him to stick it in his ear," Brooke said.

In October 2002, the Defense Intelligence Agency took over a State Department program that paid the INC $335,000 a month to gather intelligence. To qualify, Habib and other INC figures were required to take polygraph tests that focused almost entirely on his connections with foreign intelligence agencies.

"He passed," said Brooke. He said Habib acknowledged during the screening he had connections with intelligence services in Syria, Turkey, Saudi Arabia and Iran.

Brooke's account could not be independently verified.

While stirring anger among Iraqi political leaders, Chalabi's plight appears to have generated little fresh support among ordinary Iraqis who never embraced the longtime exile as a potential leader. A small protest gathered Friday in front of the Green Zone, as the compound housing occupation headquarters is known, to protest U.S. treatment of Chalabi and its failure to prevent the assassination Tuesday of the Governing Council's acting leader Izzedine Salim. But the demonstration dissipated quickly.

"It took them four years to discover he was a liar," said Ali Hashem Ali, 46, a mechanical engineer. "And it took us two days to discover he was a thief and a liar."

But Brooke said the fallout has had political benefits, particularly in galvanizing council support for Chalabi.

"This has been good for us," Brooke said. "We got what we wanted. Saddam Hussein is gone."

Staff writers Robin Wright and Thomas E. Ricks in Washington and staff writer Jackie Spinner and special correspondents Huda Ahmed Lazim and Naseer Nouri in Baghdad contributed to this report.

An Iraqi soldier keeps watch as demonstrators march in Baghdad to show support for Ahmed Chalabi.