Washington (CNN) -- U.S. officials say several key indicators bolster their initial impression that Osama bin Laden had a support network in Pakistan that resulted in his staying in one location for the past several years, feeling comfortable he would not get caught.

The officials, familiar with the latest assessment of the raid that resulted in the al Qaeda leader's death, point out there is no apparent sign that bin Laden had a ready escape plan. He did not appear to have the means or make an attempt to destroy the reams and gigabytes of documents before Navy SEALs assaulted his compound, according to the sources. The sources requested anonymity because of the sensitivity of the information.

"It looks like he became complacent," one of the officials said. "There is a lot more material than we expected to find here."

Bin Laden, one of the officials noted, had only three men with him in his Abbottabad compound at the time of the assault. U.S. officials have said that aside from bin Laden, the three men who lived in the compound and who were killed in the raid were bin Laden's son and two trusted couriers.

"What does all that mean?" the official said. "How could he be so comfortable living in that location for that period of time with so little security?"

But the number of men present is clearly open to interpretation. Other officials have speculated the low number of men on the compound could have been an effort to deflect attention. U.S. officials had long speculated bin Laden would have a retinue of guards with him.

The same official emphasized the United States is not ready to conclude bin Laden had the official support of the Pakistani government, but the indicators are bin Laden had a network of supporters.

So far, the official said, there is no indication that local citizens were providing support for bin Laden.

It was a surprise to find only three other men at the compound, the official said, and the SEALs who conducted the compound raid were prepared for a more substantial firefight.

"We plan for the worst and hope for the best," the source said, citing a standard military planning mantra.

But the low numbers did not mean residents of the compound lacked significant security and caution, the official said.

The official noted that there had been sightings of at least two couriers coming and going from the compound in the weeks leading up to the raid.

Their "quality of tradecraft was very high," he said. The couriers did not maintain a predictable schedule, and they went some distance out of town before turning on their cell phones to avoid being detected, the official explained.

While the United States was able to collect intelligence on the compound, the official said the U.S. intelligence community and military did not have continuous overhead surveillance of the compound in recent months, although drones could have been used at various points.

The source noted that unmanned drones are often visible, so the United States would not have wanted to give away hints it was watching. Continuous satellite surveillance is often costly and impractical, but by using a combination of intelligence-gathering methods, the United States was able to have near-continuous intelligence on the compound and a clear idea of who was coming and going, the official said.

The official said that after the raid, SEALs took intelligence material away in large, loose bags similar to garbage bags.

"It could take months" to fully assess the intelligence that has been gathered and the effectiveness of bin Laden's command and control of his operatives in the field, according to another U.S. official.

"If you are the CEO of al Qaeda, sometimes you focus on strategy, sometimes you focus on management or personnel," the official noted. "Over time, he was involved in all aspects," the official said, noting this is why the administration considers the compound to be bin Laden's "command and control center."

"This wasn't a retirement home for terror," the official said.

The official emphasized that bin Laden appears to have been involved in both offering strategic guidance to his followers, as well as encouraging them to attack the United States specifically.

"He had a clear and continuing interest in attacking the U.S.," the official said, adding, "We were aware he was involved in plotting. This was something he was encouraging."

The bin Laden materials being reviewed show the al Qaeda leader expressed an interest in targeting small American cities for attacks, a U.S. official told CNN.

His writings also indicate an interest in recruiting U.S. minorities to conduct attacks in the United States, the source said.

In addition, the material reflects friction between bin Laden and his followers. The communications were not "one-way," but represent a "back and forth" dialogue between bin Laden and other al Qaeda members and affiliates.

"Not everyone was on the same page in terms of strategy and operational focus" within al Qaeda, the official said.