The search for Osama bin Laden has shifted hundreds of miles north, but Pakistani and U.S. officials tell ABC News it remains centered in an area around the Pakistan-Afghanistan border where the al Qaeda leader and his deputies seem to be able to move freely.
Some of the new clues in the search come from a small Pakistani market town in the tribal region of Chitral.
The town is believed by officials to be part of the al Qaeda supply network and shopkeepers told ABC News consultant Alexis Debat this week of foreigners buying large quantities of food.
Debat says shopkeepers told him that "a group of Arabs came down from the mountains in a jeep and loaded bags of rice and flour and drove back up the mountain back to Afghanistan."
Along a rugged road and then by foot, ABC News followed the trail described by the shopkeepers to an area just short of the border where Afghanistan is visible over the mountains.
Just last month, Pakistani Army officials say they discovered an al Qaeda compound in the nearby Bajaur region, which captured fighters said was regularly used as a safe house for bin Laden's number two man Ayman al-Zawahri.
The prisoners reportedly told Army interrogators that a heavily guarded, masked man regularly visited in February and March.
"Tracking the supply lines, tracking the communication lines is something everyone is trying to do," says former CIA Afghanistan and Pakistan station chief Gary Schroen.
"It's very, very difficult there," says Schroen. "I think that the Pakistani Army movements are probably telegraphed long in advance."
Pakistani officials believe Zawahri and bin Laden move between a string of safe houses in the winter months and then retreat to mountain caves in the summer months when Pakistani forces operate.
The Pakistani Army now says it came very close to Zawahri last year when it raided another house, in South Waziristan, which they say turned out to be a hidden al Qaeda command center.
Buried underground was a huge cache of weapons, radios and sophisticated electronic equipment, including video editing machines.
Video of the secret hideaway obtained from the Pakistani Army was broadcast for the first time today on ABC News' "World News Tonight with Peter Jennings."
"It's a command and control facility because it does have radio communications," says ABC News consultant and former White House counter-terrorism chief Dick Clark, who viewed the tape obtained by ABC News.
"Exactly how many bunkers are there?" asks Clark. "And if this was a year ago it obviously hasn't led us to Zawahri or bin Laden."
Last month Pakistan's President Pervez Musharraf claimed significant progress in the fight against al Qaeda there. "We have broken their back," Musharraf said in an interview with the Financial Times.
"They cease to exist as a cohesive, homogenous body under good command and control, vertical and horizontal," he said.
However, ABC News has discovered other recent signs of unabated al Qaeda activity in the region.
A new set of propaganda tapes obtained by ABC News this week shows fighters in a night attack on what is described as a military convoy. The fighters praise bin Laden.