Osama bin Laden's compound in Abbottabad, Pakistan, was surrounded by high walls and topped by barbed wire.
Abbottabad, Pakistan (CNN) -- Investigators Tuesday were poring over a trove of materials collected from the compound in which Osama bin Laden was killed, hoping to discover clues to help break the al Qaeda network and thwart future terrorist attacks.
"We were on the compound for about 40 minutes and we were able to acquire some material that was there. A lot of that is currently being exploited and reviewed," White House senior adviser on counterterrorism John Brennan told CNN Tuesday.
"What we're most interested in is seeing if we can get any insight into any terrorist plot that might be under way so we can take the measures to stop any type of attack planning. Secondly, we're trying to look and see whether or not there are leads to other individuals within the organization or insights into their capabilities."
The search for bin Laden finally ended in early Monday's firefight, months before the 10-year anniversary of the al Qaeda network's most notorious act, the September 11, 2001, terrorist attacks on the United States.
Pakistan's GEO TV showed video Tuesday of the inside of the compound where the al Qaeda leader was living. Bottles of what appeared to be medicine, a pair of slippers, a shelf full of books and a passport of a Yemeni woman are among the items the network showed. Parts of the video seemed to show the aftermath of the firefight, with items strewn about a stained floor.
Anything collected from the scene -- from documents to seemingly mundane items -- could potentially lead investigators to other senior al Qaeda leadership.
U.S. officials say several people were killed inside the home in Abbottabad, about 50 kilometers (31 miles) north of Islamabad. There were also some children in the home, who are now in Pakistani custody, a senior Pakistani intelligence source said.
Officials have not publicly identified every person in the compound.
The jubilation in many parts of the world over bin Laden's killing gave way Tuesday to increasing questions about how the world's most wanted terrorist could have hidden for years in a populated area so close to the Pakistani military.
"How did bin Laden stay at that compound for about six years or so and be undetected?" Brennan asked. "What type of support did he have outside of that compound in the Abbottabad area or more broadly within Pakistan? We're going to look carefully at this and get to the bottom of it all."
The U.S. mission early Monday took place in secrecy, without Pakistani leadership being informed, U.S. officials said.
But Brennan insisted that "Pakistan has been a strong partner in the effort to destroy al Qaeda. More al Qaeda and other terrorists have been captured and killed in Pakistan than in any other country since 9/11. Many brave Pakistanis have given their lives in this effort against the scourge of al Qaeda. So although we may sometimes have differences of view about how this effort should be prosecuted, we are partners with Pakistan, and we'll continue to be. We appreciate their understanding that we undertook this mission. They congratulated us and we are ready to move forward with them."
In a Washington Post column, Pakistani President Asif Ali Zardari wrote that Pakistan joined other victims of al Qaeda and was pleased "that the source of the greatest evil of the new millennium has been silenced, and his victims given justice."
"Some in the U.S. press have suggested that Pakistan lacked vitality in its pursuit of terrorism, or worse yet that we were disingenuous and actually protected the terrorists we claimed to be pursuing. Such baseless speculation may make exciting cable news, but it doesn't reflect fact," Zardari wrote.
The compound where bin Laden was holed up was surrounded by walls 10 to 18 feet tall and topped by barbed wire. It sat far back from a main road and was relatively secluded. The building showed very little damage on the outside.
A neighbor said Tuesday he was stunned to learn that he lived near bin Laden.
The neighbor said if local children kicked a ball into the compound, someone from inside would pay the children for the ball rather than let them step onto the grounds.
In the wake of bin Laden's killing, U.S. officials warned that the al Qaeda leader's followers and supporters may threaten reprisal attacks. Already, one threat of revenge has surfaced.
"We are proud on the martyrdom of Osama," Ahsan Ullah Ahsan, spokesman for the Pakistani Taliban organization Tehrik-e Taliban Pakistan (TTP), said late Monday night. "We shall definitely take revenge (on) America."
When asked how the Pakistani Taliban organization would carry its vow, Ahsan said, "We already have our people in America, and we are sending more there."
Just how al Qaeda, and the organizations around the world that follow its ideology, will be affected remains in question as well. "Leadership in al Qaeda tends to be replaced," former Defense Secretary Donald Rumsfeld said Tuesday in an interview with CNN. "I expect there will be someone who will step up."
Rumsfeld, who was in office during the September 11 attacks, also took the opportunity to praise Bush administration policies that came under heated criticism.
Noting that tracking one of bin Laden's trusted couriers led the United States to bin Laden's location, Rumsfeld said, "I remember back when people were saying at Guantanamo Bay we were keeping low-level people who shouldn't have been there as detainees. They were people who were drivers or chauffeurs or couriers or bodyguards. They weren't the senior-level people. It is those individuals that know the habits and locations of the senior people. It is a good thing that the people were held and that there were interrogations and that that information was patched together over a period of time."
Monday's raid came about four years after U.S. intelligence officials identified the courier, according to senior Obama administration officials.
Rumsfeld also stood by the controversial use of waterboarding, which the Obama administration has outlawed as torture. Rumsfeld said the information taken from three people who were waterboarded and passed on to then-CIA Director Michael Hayden proved to be "enormously valuable."
Former Secretary of State Condoleezza Rice also offered praise to both the Bush and Obama administrations, saying the process that led to the killing "started a long time ago," and that Obama and his team deserve credit for finally bringing it "to a close."
While Pakistan is "an important counterterror partner," she said, "this is a time when Pakistan has got to look in the mirror and ask some hard questions."
Obama plans to visit New York Thursday to meet with families of those killed in the attacks and to visit the World Trade Center site, now being rebuilt but still widely known as "ground zero."
The 9/11 attacks prompted a U.S. invasion of Afghanistan in pursuit of al Qaeda and its allies in the Taliban, the fundamentalist Islamic militia that ruled most of the country at the time.
"I hope now the world (has) realized that Afghanistan was not a haven for al-Qaeda, but it was in Pakistan -- and that has always been pointed out by Afghans," Fatima Aziz, an Afghan parliament member, said Tuesday.
Bin Laden was the son of a prominent Saudi construction magnate. He turned against the Saudi monarchy when it agreed to allow U.S. troops into the kingdom during the 1991 Persian Gulf war and launched his jihad against the United States in 1997.
He had been implicated in a series of deadly, high-profile attacks that had grown in their intensity and success during the 1990s. They included a deadly firefight with U.S. soldiers in Somalia in October 1993, the bombings of two U.S. embassies in East Africa that killed 224 in August 1998, and a bomb attack on the USS Cole that killed 17 sailors in October 2000.