Five years ago this week, on December 30, 2009, Jordanian doctor Humam Khalil Abu Mulal al-Balawi carried out the single most successful direct attack on the American national security operatives responsible for targeting and killing al-Qa’ida members post-9/11, when he detonated his explosive vest within the wire of FOB Chapman—CIA’s Khowst Base—killing five CIA officers and two contractors who had gathered to debrief him. The CIA, along with Jordanian intelligence, believed al-Balawi was on our side, and a potentially valuable source to report on al-Qa’ida senior leadership. We were horribly wrong.

The operation was not only a direct strike on officers of the CIA’s Counterterrorism Center (CTC), the lead agency within the U.S. Government responsible for hunting down al-Qa’ida members worldwide, it was also a devastatingly successful “double” operation, run against one of the world’s premiere intelligence agencies. Instead of being “our man,” al-Balawi was working for al-Qa’ida—in cahoots with the Pakistani Taliban. A double agent for the enemy.

It takes a certain level of sophistication to run such an operation. A sophistication that, frankly, many of us doubted al-Qa’ida, let alone the Pakistani Taliban, possessed. In short, it took the Agency by surprise, and the result was tragic. The attack was, and remains, al-Qa’ida’s most notable operation against America since 9/11.

Just how did this happen?  How could the CIA have been fooled?  At least some within the Agency, according to press reports, had their doubts about al-Balawi and his intentions. Those skeptics reportedly included Amman-based CIA Case Officer Darren LaBonte, who expressed his reservations about the meeting. He thought the Agency was moving too fast with al-Balawi, and that the Jordanian doctor was trying to control too many details of the planned meeting. LaBonte suspected something nefarious might be going on, according to the above press report.

Essentially, LaBonte’s case-officer instincts were kicking in, and something did not feel right to him. Tragically, events moved forward, and the meeting went ahead as planned. LaBonte’s instincts would sadly prove correct, but would fail to save him from al-Balawi’s explosives. He died along with the Jordanian intelligence officer who accompanied him to Khowst for the meeting, as well as six other CIA personnel.

The point of this piece is not to lob recriminations at the CIA or Jordanian officers involved in the operation—I was not involved, and can’t judge—but rather, to acknowledge that al-Qa’ida carried out a terribly effective operation, and to remind everyone that it remains the only such successful AQ operation, killing CIA officers, run against the Agency in over 13 years of war.

Could things have been done differently within the organization? Of course they could have. They always could. An internal review found that the Agency was too eager to meet al-Balawi, who offered tantalizing locational data on al-Qa’ida deputy Ayman al-Zawahiri. Agency personnel are fallible, and near-constant vigilance in the war on terror sometimes ebbed, especially when a potentially valuable target came into view. In this case, a terrible confluence of events combined with that ebbing vigilance to result in tragedy.

Yes, the attack succeeded, and al-Qa’ida killed seven CIA personnel who were directly targeting the group. The terror group failed, however, to stop the CIA from continuing to hunt its leaders and decimate its ranks. The CIA took a hit, but the Agency persevered through it, and re-doubled its efforts. We all know that less than two years after the attack on Khowst, the Agency’s CTC found Bin Ladin, and with the help of the U.S. military, put an end to his life. We will find Zawahiri, too.  It is only a matter of time.