The first official report on the Sept. 11 attack on the U.S. mission in Benghazi, Libya, appropriately focuses on the failures of security and intelligence that allowed the compound to be overrun, leading to the death of Ambassador J. Christopher Stevens and three other Americans.

According to the Accountability Review Board established by the State Department, “systemic failures of leadership and management deficiencies at senior levels within two bureaus of the State Department resulted in a security posture that was grossly inadequate to deal with the attack that took place.”

Intelligence agencies failed to connect the dots between the deteriorating security situation and the proliferation of “violence prone and little-understood militias,” the board found. Bureaucrats at State, meanwhile, resisted repeated requests for additional security officers.

The report makes an important start toward establishing accountability for Benghazi and preventing a repeat at other missions. Four officials at State were reported to have resigned under pressure Wednesday. The board offered two dozen recommendations, which Secretary of State Hillary Rodham Clinton said she accepted and had ordered a task force to implement. Prominent among them is the need for adequate funding for embassy security by Congress; the report notes that chronic budget pressure had conditioned State’s managers to reflexively resist spending.

The board offered a needed corrective to some of the false charges and conspiracy-weaving about Benghazi. Contrary to claims by Fox News, the investigation found no evidence that a security force at a nearby CIA mission was slow in responding to the attack; it also discounted suggestions that U.S. military assets could have been brought to bear during the attack.

But the most important piece of accountability remains untackled. Though it confirmed that the mission suffered an organized terrorist attack that did not, as the intelligence community initially reported, arise out of a demonstration, the board did not attempt to identify who carried it out, saying that should be determined by an FBI investigation. But there is little sign of movement in that probe; in a Wednesday statement, House Intelligence Committee Chairman Mike Rogers, R-Mich., reported “a near total lack of progress bringing these terrorists to justice.”

The reality is that stronger tools than criminal investigations and diplomacy will almost certainly be needed to neutralize the Benghazi attackers. The longer the delay, the greater the danger they will strike again.