Now that Saddam Hussein has been caught, the pressure is on to find the other top target in the war on terror. Why is it proving so hard to find Osama bin Laden?
"Bin Laden's on the run," President Bush told ABCNEWS' Diane Sawyer Tuesday in his first interview since Saddam's capture at the weekend.
The leader of the al Qaeda terror network will face a similar fate as that of the deposed Iraqi president, Bush said. "He's certainly not leading any parades these days," Bush said, referring to bin Laden. "He's probably in a hole somewhere hiding from justice. We'll get him."
The last time the U.S. military believed it knew exactly where bin Laden was hiding was two years ago, when it bombed the mountains of Tora Bora, Afghanistan.
The most recent American intelligence puts bin Laden somewhere in, or near, the mountains in the Pakistani province of Waziristan.
The region's rugged terrain, which ABCNEWS visited earlier this year, is home to fiercely independent tribes hostile to the Pakistani government or any other outside force.
The tribes and the terrain make the search for Saddam Hussein seem easy in comparison, says Akbar Ahmed, a former official in Waziristan.
"[There are] formidable fighting tribesmen who resent any outsider coming into the area," said Ahmed, who is now a professor of International Relations at American University in Washington, D.C. "Osama, if he's there, would be there as a guest. And the code of the people there is that if a guest is living there they will protect him with their lives."
Pakistan does not allow U.S. forces to operate in Waziristan, so American troops or operatives are unable to go into the marketplaces where money handlers and merchants might provide the kind of clues that led to Saddam Hussein's hideout in Iraq.
"We have to work through the Pakistanis," said Richard Clarke, an ABCNEWS consultant who was a national security adviser at the White House before retiring earlier this year, "and in Pakistan there are vast areas that are hostile to even the Pakistanis. So it's very, very difficult to do the kind of controlled search we did in Iraq."
Need for On-the-Ground Intelligence
U.S. satellites constantly cover the area, looking for movement, vehicle caravans and unusual activity in certain Waziristan villages. But satellite analysts say the coming winter months mean more cloud cover blocking the view from imagery, but also present certain opportunities.
"You'll be able to see fresh tracks in the snow," said Tim Brown, an imagery analyst with GlobalSecurity.org, and be able to see how often a particular area has been visited.
U.S. officials believe they've narrowed bin Laden's whereabouts to a 40-square-mile area of Waziristan, but say it won't mean much without the kind of real-time human intelligence that led to the capture of Saddam Hussein.
"It took us about seven months of looking to find Hussein, and it so far has taken us more like 30 months going after bin Laden and we're still nowhere near being able to develop a methodology for getting bin Laden," said Richard Clarke. "I think the chances of getting bin Laden are pretty remote."
U.S. and coalition troops across the border in Afghanistan have recently been trained in non-lethal methods of capture and equipped with canisters of knockout gas. But officials say the most likely scenario would involve a sighting of bin Laden by air or satellite, followed by a massive missile strike.
Authorities are casting a net around the towns of Angoor Ada and Wana in southern Waziristan, which are believed to be filled with al Qaeda supporters. But it is a difficult and dangerous area to operate in.
Protected by local gunmen, an ABCNEWS producer, whom we won't name due to safety reasons, was able to move through the hostile Waziristan area undetected this summer.
Read the producer's exclusive reporter's notebook.
Local residents showed ABCNEWS the mountain homes of known al Qaeda operatives, graffiti praising the Taliban leader Mullah Omar, who is also believed to be hiding in northern Waziristan, and the marketplaces and bazaars where authorities believe that bin Laden and his entourage could get their supplies.
At least eight people were murdered in the town of Angoor Ada, in broad daylight, on the suspicion they were informing U.S. forces of bin Laden's whereabouts, according to locals. As a result, locals are tight-lipped about al Qaeda's presence.
Locals also told ABCNEWS that one tribe has been known to kill their own relatives for helping Americans with development and infrastructure work on either side of the Afghan-Pakistan border.
"I think it's highly risky for anyone up there," said Clarke. Since the majority of people in that region support bin Laden, he said, "they are going to be enforcers and they're going to be protecting him and his organization."
Bin Laden’s Messengers
Even though bin Laden has continued to issue audiotapes confirmed by the CIA as his voice, he was last seen on a video on April 15, 2002. Four months earlier, when he released a tape claiming credit for the Sept. 11, 2001 attacks, his gaunt appearance suggested he was ill or injured.
But authorities told ABCNEWS information from electronic intercepts and intelligence on the ground shows bin Laden is very much alive. Local sources in Pakistan said al Qaeda has affiliates in different cities from Wana to Karachi, who are responsible for transporting al Qaeda members and sending messages by camel, enabling bin Laden to avoid U.S. spy planes and satellites overhead.
"The problem has been that bin Laden has gone quiet," said former CIA counter-terrorism chief Vince Cannistraro, who is also an ABCNEWS consultant. "He is not using electronic communications devices. And there haven't been any recent sightings of him."
Earlier this year, electronic intercepts focused U.S. intelligence on another region of Pakistan — Baluchistan — where authorities thought they had found bin Laden moving in a convoy of trucks.
"They thought they were very close to locating him and fixing his position," said Cannistraro. "But they failed in the end to locate him."
Tribal Codes, Customs
Four FBI and CIA agents are stationed with Pakistani troops to relay U.S. intelligence information, but even the Pakistanis have a hard time operating there. By treaty with the Wazir tribe, Pakistani government forces are not allowed further than 100 yards on either side of the road, according to Ahmed.
"This really is a closed area," he said. "The government of Pakistan has very limited control."
Pakistani officials have had some success in tracking down and apprehending some key al Qaeda members, including Khalid Shaikh Mohammed, one of bin Laden's top deputies accused of planning the Sept. 11, 2001, attacks and captured March 1 in Pakistan. But according to Pakistan Interior Minister Makhdoom Faisal Saleh Hayat, they have been handicapped by centuries-old tribal traditions and customs.
"Because of their tribal sensitivities, it could be entirely possible that Osama, or his other aides — his closest aides — they could be in hiding in parts of the tribal belt," said Saleh Hayat.
The tribes also cross borders between Afghanistan and Pakistan, "so Osama can be like a fish swimming in an ocean, just going up and down," said Ahmed.