Bagram, Afghanistan ? Braced for booby-traps and hidden tripwires, American soldiers searching elaborate cave complexes along the Pakistan border found jail cells and dossiers complete with photographs and fingerprint samples.

After landing at Bagram air base Saturday aboard waves of Chinook helicopters, men from the 101st Airborne Division recounted the 5-day mission into the Zhawar Mountains that took them deep into enemy caves in a hunt for intelligence information before they destroyed the abandoned hide-outs.

The mission, dubbed Operation Mountain Lion, took about 500 troops to an area not far from where American forces battled Taliban and al-Qaida fighters in last month’s Operation Anaconda. But the soldiers, many of whom fought in Anaconda, said this mission was different because of the absence of fighting and the feeling that they had found a key spot.

“The locals were saying these were the caves where Osama bin Laden was, and we were destroying munitions and felt like we were doing something important,” said Capt. Lou Bauer, 29, of Windsor, N.Y.

U.S. and other allied special forces units have been in the area of Paktia province off and on in recent months, identifying cave hide-outs and looking for intelligence to be used in the hunt for al-Qaida and Taliban forces. Operation Mountain Lion was launched to send in a larger force go through caves inch-by-inch, remove all relevant information, then blow them up.

“A battalion of 500 searching is different from a few people,” Maj. Bryan Hilferty, a U.S. military spokesman at Bagram, said. “So we thought from the intelligence and evidence we saw it was worthwhile for us to go back again.”

The mission took the troops through a dry, narrow valley – like a creek-bed – between two mountains. The caves, some well-hidden and others with openings like small roman arches, opened onto the valley. The valley is a road for some locals, and soldiers described seeing sporadic traffic of people, camels, sheep, and one truck.

The troops searched and destroyed some 15 caves. Man-made and built into mountainsides, the caverns were interconnected and formed networks of tunnels. Bauer had drawn a map with pencil that went on for three pages, showing how one cave went some 1,000 feet deep.

When other methods did not work to destroy the caves, some of which were fortified with brick walls, steel beams and reinforced ceilings, Army engineers used C-4 explosives to bring them down, Bauer said.

The searches netted five trash bags full of documents, including folders that looked like dossiers, with photos and fingerprint samples attached. Soldiers also came across medical supplies, including syringes and antibiotics, rocket propelled grenades and, deep inside one cave – three cells with bars.

Hilferty would not comment on what was found in the documents nor the value of the other information, but said “everything that we find is significant.”

The soldiers said they also encountered their share of mysteries that will now be up to intelligence officers to sort out.

In many caves they found white powder everywhere, and jars of it in an abandoned village nearby. Sitting on their duffel bags at Bagram, soldiers also wondered among one another about the purpose of a T-shaped trench, 3 feet wide and 5 feet deep, found in one cave.

Perhaps the most out-of-place item located was a copy of USA Today from May 17, 2001.

Local Afghans were friendly, the soldiers said, and there were anti-Taliban forces running checkpoints on many hilltops. An Associated Press photographer heard an Afghan soldier tell an American officer that some 800 al-Qaida and Taliban soldiers had regrouped a few miles away, just over the border, in Pakistan. The soldier, translating for his commander, complained that “the Pakistanis aren’t doing anything about it.”

The Pakistani government insists it is patrolling the border vigilantly.

The Americans encountered no hostility – neither from locals whose villages they trooped through nor from enemy forces. The only combat sounds they heard were those from locals celebrating one night, banging steel pipes, singing and firing off their guns.

On a search of the village of Shodiaka, which locals said had been recently abandoned, soldiers found made beds, children’s books and food. Nearby, they came across a cemetery of hundreds of graves, marked by stones and colorful flags. In the cemetery was a small, clay building, just big enough for a table inside. Spread out on the table was a not-yet decomposed body, covered with brightly colored blankets.