The investigation report said that in the weeks prior to the attack there had been numerous breaches of Bastion's supposedly secure perimeter, some of which had been captured on surveillance videos. One video showed an individual who entered the base through a hole in its perimeter chain-link fence, "looked around inside an empty guard tower and departed again."
It said many people, including Gurganus, who was the commander of all coalition forces in southwestern Afghanistan, had expressed concern about the breaches but "accepted them" as related to theft or other incursions that did not necessarily pose a security danger to the Marines.
The report faulted Gurganus for failing to take sufficient actions to ensure security prior to the attack.
"He underestimated the threat posed by the enemy's capabilities, overestimated U.S. and coalition capabilities to counter that threat and failed to take prudent steps to counter or mitigate an enemy attack," it concluded.
Sturdevant, who commanded the Marine aviation unit in the region, mistakenly assumed that other military units on Bastion would provide adequate protection for his aviation forces, the report said.
"This misjudgment unnecessarily exposed his personnel and equipment to enemy attack," it said.
Sturdevant and Gurganus issued statements Monday saying they respected Amos' decision.