ABC's Jake Tapper, Sunlen Miller and Tahman Bradley report: Tensions were thick in the White House Situation Room after two choppers full of Navy SEALS left Afghanistan to storm a Pakistani compound and kill Osama bin Laden. The President wasn’t 100% certain bin Laden was in the compound. No one was. The operation was a surgical raid by a small team designed to minimize collateral damage and pose as little risk as possible, to Pakistani civilians in the neighborhood, senior administration officials said. The SEALS raided the compound. A firefight ensured. Bin Laden fired back, as did others in the compound. After 40 minutes of fighting, bin Laden, two couriers, and one of bin Laden’s adult sons were killed, as was a woman used as a shield by one of the male members of al Qaeda. Two other women were injured. During the raid one helicopter was lost due to mechanical failure. The aircraft was destroyed by the crew. Carrying bin Laden’s dead body, the SEALS boarded the remaining helicopter to exit the compound. White House national security staffers had been in the Situation Room since 1pm ET. At 2:00pm the President met with the Principals to review final preparations. At 3:50pm the President was told bin Laden had been tentatively identified. There was jubilation in the White House once the helicopter returned to Afghanistan. At 7:01 pm President Obama was told there was a “high probability” bin Laden was dead. “The death of Osama Bin Laden marks the single greatest victory in the US-led campaign to disrupt, dismantle, and defeat Al Qaeda,” an official said. The operation had been in the works for years. Since 9/11, the CIA gathered leads on those in bin Laden’s inner circle, including personal couriers. During interrogations and questioning, various detainees flagged individuals who may have been providing support to OBL and Zawahiri. One courier in particularly was identified by detainees as one of the few al Qaeda couriers who had bin Laden’s trust. He was identified as a “protégé” of Khalid Sheikh Mohammad and a trusted assistant of Abu Faraj al –Libbi, the former #3 of al Qaeda, who was captured in 2005. There were even indications the courier may have been living with bin Laden. In 2007, intelligence officers discovered his identity. In 2009, intelligence officials identified areas in Pakistan where the courier and his brother operate – but they were still unable to pinpoint precisely where. In August 2010 came a big break. Intelligence identified a compound that aroused their suspicion – eight times larger than other homes in the area, built in 2005, on a property valued at $1 million. But access to the compound was severely restricted, with elaborate security and 12 to 18 foot walls topped with barbed wire. Incongruently, the compound has no phone service or televisions. The main building had few windows and a seven foot wall for privacy. Residents burned their trash. Intelligence officials concluded that unit was “custom built” to hide someone. A third family was identified as living there – and the size and makeup matched the bin Laden family members most likely with him. The location and design of compound were consistent with what experts expected his hideout might look like. Their final conculsion: there was a strong probability that this was bin Laden’s hideout. While he publicly downplayed the importance of capturing or killing bin Laden, on June 2, 2009 President Obama had signed a memo to the director of the CIA, Leon Panetta, stating “in order to ensure that we have expanded every effort, I direct you to provide me within 30 days a detailed operation plan for locating and bringing to justice Usama Bin Ladin…” Beginning in September of 2010 the CIA began to work with the president on a set of assessments that led him to believe that in fact it was possible that bin Laden may be located at that compound. The president was was told it contained “a key al Qaeda facilitator appeared to be harboring a high-value target.” The president directed action to be taken “as soon as he concluded that the intelligence case was sufficient.” By mid February, though a series of “intensive” meetings at the White House and with the president, administration officials determined there was a “sound intelligence basis” for pursuing this “in an aggressive way” developing course of action in pursuit of bin Laden at this location. By the middle of March the president began a series of national security meetings that he chaired to pursue again the intelligence that had been developed and a course of action. The president chaired no fewer than five national security council meetings on this topic – on March 14th, March 29th, April 12th, April 19th and April 28th. “When a case had been made that this was a critical target we began to prepare this mission in conjunction with the US military,” a senior administration official said. At 8:20am on Friday, April 29th in the Diplomatic Room, President Obama met with National Security Adviser Tom Donilon, White House chief of staff William Daley, White House counterterrorism adviser John Brennan and deputy National Security Adviser Denis McDonough and gave the order for the operation. Officials said only a very small group of people knew about the operation beforehand. “That was for one reason and one reason alone, we believed that it was essential to the security of the operation and our personal,” an official said. “Only a very small group of people inside our own government knew about this operation in advanced.” Shortly after the raid, U.S. officials contacted senior Pakistani officials to brief them on the results of the raid. They also contacted a number of close partners and allies in the world. Officials say the administration is ensuring bin Laden’s body is being “handled in accordance with Islamic practice and tradition.” “In the wake of this operation there may be a heighted threat to the homeland and to U.S. systems and facilities abroad,” an official cautioned. “Al Qaeda operatives and sympathizers may try to respond violently to avenge Bin Laden’s death and other terrorist leaders may try to accelerate their efforts to strike the United States. But the United States is taking every possible precaution to protect Americans here at home and overseas.” Asked if U.S. officials are hearing of specific threats against specific targets, the officials said, “no.” The State Dept. has sent guidance to embassies worldwide and a travel advisory has been issued for Pakistan.