The US bombing campaign in Afghanistan has tapered off in recent days, but perhaps the most vital phase of the two-month-long conflict is just beginning: the battle to extract nuggets of intelligence from the rubble of war.
US officials are beginning the tricky work of interrogating Al Qaeda and Taliban captives, including suspected senior leaders, selected from the hundreds now detained in Afghanistan and Pakistan, Pentagon officials say. The number of war captives in US custody - 20 at latest count - is expected to grow and could mount to more than 100, the officials say.
Meanwhile, US ground forces are combing caves, tunnels, homes, and compounds - producing mounds of documents, as well as computer hard drives, and phone books to sift through.
The US military is also testing and searching more than 50 sites in Afghanistan potentially used by terrorists to build chemical, biological, or other weapons of mass destruction.
The overarching goal is to unearth fresh details about how Al Qaeda and other terrorist networks operate globally and about past and potential future terrorist attacks - an aim US defense officials suggest is more important to American security than finding the group's fugitive leader, Osama bin Laden.
"You could have Osama bin Laden walk in here this minute and turn himself in and say he's sorry, and the Al Qaeda network would exist," said Defense Secretary Donald Rumsfeld this week. "[Al Qaeda] has businesses across the globe. It has sleepers in various countries. It has cells. It has money. It has communication capability. And it has, I'm going to guess, one or two handfuls of people who are perfectly capable of continuing to operate that network."
Mr. Rumsfeld voiced optimism that the Afghanistan campaign is producing a "treasure trove" of new intelligence on Al Qaeda as the US-led antiterror coalition rounds up fleeing Al Qaeda members in Afghanistan and Pakistan.
Nevertheless, obtaining that intelligence - especially from the mainly Arab, Pakistani, Chechen, and other non-Afghan radicals who make up the Al Qaeda captives - is a difficult task complicated by security risks, language problems, and legal and diplomatic considerations.
"Having a prisoner is a pain in the neck," Rumsfeld told a Pentagon briefing Wednesday. "You've got to disarm them. You've got to make sure they don't get away," he said, indicating the manpower needed to manage prisoners was taking US personnel away from their main mission.
Most of the 15 detainees held since Tuesday by US forces at a barbed-wire prison camp beside Kandahar airport arrived roped together, wearing blindfolds, and had their feet and hands shackled in flexible cuffs.
The detention facility can hold about 100 captives, with room for another 100 at the Marine base known as Camp Rhino southwest of Kandahar, Pentagon officials said.
Another five detainees, including the American John Walker and three people identified by the Pentagon as likely senior Al Qaeda or Taliban members, are being held aboard the USS Peleliu.
The security risks were underscored Wednesday when dozens of suspected Al Qaeda fighters who had been captured fleeing across the border broke away from their Pakistani guards, instigating a shoot-out in which 13 people were killed.
Screening and identifying potential sources from among the hundreds of suspects pose another hurdle, since senior leaders are likely to attempt to pass themselves off as rank-and-file fighters, officials say.
"These guys aren't going to walk out with a nametag on their uniform saying they are a senior Al Qaeda leader," says Maj. Brad Lowell, a spokesman for the US Central Command in Tampa, Fla. "We are early in the screening process, and clearly they are skilled at the art of deception."
Once suspects are selected and handed over to the United States, officials say they will use a variety of tools - ranging from old-fashioned police interrogation tactics to offers of cash, US residency, and other incentives - to get them to talk.
"You ask them questions you already know the answers to, so when you are interviewing someone, you can cut through the [lies]," said one defense official.
US legal concerns about how to classify the detainees, as well as the need for coordination between different law-enforcement agencies and the military, appear to be slowing and complicating the interrogations.
For instance, the US military is handling the detentions and other intelligence-gathering in Afghanistan according to the laws of armed conflict. However, a team of FBI investigators that arrived this week to question the Kandahar detainees must operate under the same rules of procedure that the FBI uses to interview suspects on US soil.
Diplomatic questions may also arise, especially as the United States makes it clear that it will seek custody of any Al Qaeda terrorist suspects now held in Pakistan. Pakistan's willingness to crack down on Al Qaeda has been questioned due to its longstanding ties to the Taliban regime that sheltered Mr. bin Laden and his network in Afghanistan.