WASHINGTON – The CIA and members of Congress said they want to know how a presidential commission unearthed details on intelligence failures about Iraq’s pre-war weapons programs that previous investigations missed.

Of particular interest is information that emerged in last week’s report about how doubts were handled regarding a leading source on Saddam Hussein’s alleged mobile biological weapons labs – an Iraqi scientist who defected to Germany, code-named “Curveball.”

Porter Goss, who became CIA director last September, has instructed officials to determine what happened and why the details did not come to light earlier, said his spokeswoman, Jennifer Millerwise.

“It was an unhappy surprise to the director that his first understanding of this issue was when he first read” the commission’s report, Ms. Millerwise said yesterday.

Senate Intelligence Chairman Roberts, a Republican of Kansas, also acknowledged President Bush’s intelligence commission had details that did not emerge during his committee’s year-long investigation into the Iraq assessments, released last July.

If Mr. Bush’s intelligence commission learned “something obvious,” Roberts said, “we want to make sure the intelligence community does fill in those gaps so we have a clear picture.”

Other lawmakers are angrier. “As far as I am concerned, the CIA threw us a curveball,” said Senator Levin, a Democrat of Michigan, also a member of the Intelligence Committee.

The White House, Congress, and American intelligence agencies have launched a number of investigations into the faulty pre-war intelligence on the Iraq threat. The most definitive to date came last week from Mr. Bush’s intelligence commission.

According to the report, CIA officials tried to tell the agency’s top officials that Curveball was a suspected fabricator and may have been mentally unstable. The new information includes an alleged warning in a late night phone call to George Tenet, the agency’s former director.

Mr. Tenet and his top deputy have both released statements emphatically denying that they received such warnings. Mr. Tenet called it “deeply disturbing” that the information didn’t get to him.

Mr. Levin wants Tenet to testify under oath. “I don’t think the intelligence committee was given some of that detail on Curveball, but I think it should have been,” Mr. Levin said.

“Tenet said he doesn’t remember,” Mr. Levin said. “Hey, these are life and death decisions. This is what we tell the world. That’s not good enough. …Where is the responsibility?”

American intelligence agencies and the Bush administration have come under fire since 2001 for not sharing enough information with lawmakers who oversee some of the government’s most sensitive intelligence activities. Some in Congress have been particularly concerned about American detention policies and the botched Iraq intelligence that was used to justify the invasion.

When asked how the new investigation got more detail, Senator McCain, a Republican of Arizona, and a commission member, said that the panel conducted numerous long interviews. “We did not come up with that information early,” Mr. McCain said of the information on Curveball.

Last week’s report said the Defense Intelligence Agency circulated more than 100 reports from Curveball, with detailed information about mobile biological weapons labs in Iraq.

Curveball was working with German intelligence, and American intelligence had limited access to him. The report said Curveball met once with a defense official and seemed to have a hangover.

The report said CIA officials contended that they tried to raise warnings about Curveball. One unnamed CIA division chief claims to have called Tenet at midnight the night before former Secretary of State Powell gave his address to the United Nations, which provided the Bush administration’s case for invading Iraq. The division chief recalled telling Mr. Tenet that foreign intelligence officials were concerned about Curveball’s credibility.

In an unusual seven-page statement last week, Mr. Tenet said his “strong recollection” is that he did not speak with the division chief around midnight.

Mr. Tenet also said it was “stunning and deeply disturbing that this information, if true, was never brought forward to me by anyone” when the Iraq intelligence was scrutinized.