Usama bin Laden's Pakistan compound was "built for deception," with barricades and a false wall apparently intended to confuse and stall intruders, a senior U.S. official told Fox News.

The official said the compound was constructed in anticipation of a "potential assault." Every floor had barricades and what looked like the main door of the complex had a brick wall behind it.

These details and others suggest that bin Laden had a contingency plan for getting out alive in the event of a surprise raid. Though he was unarmed and unguarded when the CIA-led Navy SEALs team arrived Sunday with orders to capture or kill, he had taken some basic precautions. In the end, they weren't enough to save him.

Those precautions could be seen in the design of the compound and bin Laden's lifestyle. Not only was the complex built to slow intruders, it had no phone or Internet. The lack of an "electronic signature" was one factor that convinced CIA Director Leon Panetta bin Laden was probably living there, the official said.

Bin Laden also seemed to have a very simple getaway plan -- at the time he was killed, he was carrying 500 euros (about $746) and two telephone numbers sewn into his clothes, suggesting that, in the event of a raid, bin Laden thought he might be tipped off in time to escape with the bare essentials.

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The circumstances surrounding his final minutes are still a bit blurry. Lawmakers continue to receive briefings, and former President George W. Bush is expected to be given a full intelligence briefing imminently, Fox News has learned.

A senior U.S. official said that while bin Laden was unarmed, he appeared to be reaching for a weapon before being fatally shot.

The White House says bin Laden resisted. Panetta, in an interview Tuesday with PBS, said U.S. forces had to engage in "firefights" as they made their way through the compound, and when they got to bin Laden, "there were some threatening moves that were made that clearly represented a clear threat to our guys. And that's the reason they fired."

"And obviously, under the rules of engagement, if he had in fact thrown up his hands, surrendered and didn't appear to be representing any kind of threat, then they were to capture him. But they had full authority to kill him," Panetta said.

The team encountered resistance "throughout the operation," White House Press Secretary Jay Carney said.

Providing a thorough timeline of the operation, Carney said the raid started with one U.S. team working its way up from the first floor of the main building, where bin Laden's family and one other family lived. Another U.S. team cleared a separate building on the compound where yet another family had been living alongside bin Laden.

The first team killed two Al Qaeda couriers and a woman who got caught in the crossfire on the first floor of the main building, Carney said. The team found bin Laden and his family on the upper two floors.

According to one source, 10 people who were likely family members were in the room with bin Laden, including several young children, as well as one of his wives. Some of the children ran out of the room during the fighting. There was also a toddler in the residence.

Carney, after tripping up on some of the finer details and acknowledging he was a bit "confused," said bin Laden's wife "rushed" somebody from the U.S. team but was shot in the leg. Carney said bin Laden also resisted and was killed after that. After the completion of the mission, the team gathered evidence and took the body away from the scene.

That data and evidence are now being analyzed by CIA staff at the agency's Virginia headquarters. "The U.S. is moving quickly to exploit this information before the cockroaches scatter," a senior defense official said.

A congressional source told Fox News on Wednesday that the material "could take some time" to evaluate and some of it will need to be translated from Arabic.

But the cache of information has been described as a significant find.

One former senior intelligence official said the data could be "invaluable as a history of the network" and, at the very least, "an encyclopedia of who's who."

Al Qaeda rifles and pistols were found on site in addition to computer hardware and documents, an official told Fox News.

The official also said that in the run-up to the operation, SEALs trained on a "to-scale" compound built inside the United States at a secret location. The code name for the operation was "Neptune's Spear."

Fox News' Catherine Herridge and Jennifer Griffin contributed to this report.