sentences:  On the night of 11–12 May 2007, the aforesaid U.S. military observation post near Mahmoudiyah, with two armored Humvees, 165 feet apart and facing in opposite, outward, directions, 
  each with four soldiers, seven of them U.S., one Iraqi soldier, sat guard,
  looking for insurgents planting explosives,
  and was ambushed and attacked by a group using automatic weapons and explosives.Four U.S. Army soldiers and the Iraqi soldier-interpreter were killed