On July 4, 2009 combat outpost Zerok in East Paktika Province was attacked. The Haqqani network insurgents attacked the COP using mortars, accurate heavy machine gun fire, RPG fire, recoils rifles, and a 5000 lbs Jingle Truck VBIED that destroyed the outposts radio communication. The accurate enemy indirect fire from their mortars set the US mortar pit on fire, and killed two Able Company, 3rd Battalion 509th parachute Infantry regiment mortarmen, PFC Casillas and PFC Fairbairn. They were both returning fire on the 120mm mortar. After the VBIED went off, multiple insurgents began maneuvering towards the outpost, some getting within 100 meters of the cop. Because the enemy was advancing so close to the outpost, the request for CAS was called in, but because of the DUSTWUN (large scale search) for PFC Bergdahl, (who went AWOL after abandoning his post only 100 km away from COP Zerok), air support was delayed. After intense fighting the US Paratroopers suppressed and killed most of the enemy, eventually gunships arrived and JDAMs were dropped on enemy targets.