In February, the U.S.-led coalition in Iraq made public an intercepted letter it said was written by Abu Musab al-Zarqawi to al Qaeda leaders, detailing a strategy of spectacular attacks to derail the planned June 30 handover of power to the Iraqis.
U.S. officials say al-Zarqawi may have been involved in some of the series of suicide bombings this year in Iraq — including the massive mosque bombings on Tuesday that killed more than 100 Shiite Muslims.
But according to a statement circulated this week in Fallujah, a hotbed of anti-U.S. insurgency activity, al-Zarqawi was killed in northern Iraq "during the American bombing there."
The Fallujah statement called the al-Zarqawi letter "fabricated," saying it has been used by the U.S.-run coalition "to back up their theory of a civil war" in Iraq.
The claim reflects the murky enemy U.S. troops are fighting in Iraq. American officials agree foreign fighters are now the main resistance. But determining who they are, and how they operate, has proven difficult.
The Washington Post reports violence and turnover have hampered the CIA as it tries to answer those question.
In other developments:
In a sign of the bitterness over the lack of security, several thousand Shiites in chanted anti-U.S. slogans in one funeral procession. "No, no, Americans! No, no Israel! No, no, terrorists!" they shouted, carrying three coffins through Karbala's streets. Some took a sheet painted to look like an American flag and set it ablaze.
Grand Ayatollah Ali al-Husseini al-Sistani and other Shiite leaders also accused the coalition of failing to provide adequate security for the worshippers and of not doing enough to prevent extremists from crossing Iraq's porous borders.
In what appeared to be a nod to the criticism, U.S. administrator L. Paul Bremer said the coalition would help strengthen border security.
No group claimed responsibility for the attacks. However, the top U.S. commander in the Middle East, Gen. John Abizaid, said Wednesday that the United States has evidence that al-Zarqawi was behind the bombings.
That evidence was contradicted by the insurgents' statement, which said al-Zarqawi died when he was unable to escape U.S. bombing because of his artificial leg.
The statement, which could not be verified, did not say when al-Zarqawi was supposedly killed, but U.S. jets bombed strongholds of the extremist Ansar al-Islam in the north last April as Saddam Hussein's regime was collapsing.
Bremer said Wednesday it was "increasingly apparent" that "a large part of terrorism" comes from outside Iraq. But the insurgents' statement denied that.
"The truth is, al Qaeda is not present in Iraq," the statement said. Though many Arabs entered the country to fight U.S. troops, only a small number remain, it said.
America's intelligence officers are having a hard time pinning down who is right.
The Post reports that the CIA now has four times as many spies in Iraq as it planned — 300 — making it the largest CIA station in the world, and the largest foreign station since the Saigon office during the Vietnam war.
But because of ongoing violence, CIA officers are required to travel with bodyguards, making it difficult to gather information inconspicuously.
And in order to fill their staffing needs, the CIA has asked retired officers to join the Iraq operation. To entice them and other officers to take Iraq assignments, the agency keeps them in country for as little as 90 days. The station chief was replaced in December, reports The Post.
Since midsummer, U.S. officials have struggled to understand who is behind the violence that initially was aimed mainly at American troops but recently has been directed more at Iraqi civilians.
U.S. and allied forces have chipped away at the leadership and financial underpinnings of the anti-occupation insurgency, which the military calls "former regime elements."
The holdouts from the defeated Saddam regime remain elusive and frequently effective in their attacks. But as that threat has weakened, other dangers have grown, chiefly from terrorist groups whose shape, scope and origins have been difficult for the Americans to define.
On a trip to Iraq last month, Abizaid expressed his oft-stated view that public reports of large numbers of foreign terrorists entering Iraq are overstated. Commanders on the ground generally agreed with that assessment.
But some commanders said they are worried most about what they call Islamic fundamentalists, whom they differentiate from terrorists, although both groups include foreigners.