On the night of August 21 , a group of internally displaced people was overtaken beside the Amatitán river by the Atlacatl Battalion , a US-trained counter-insurgency unit . The Atlacatl Battalion had previously been responsible for the El Mozote massacre , in which up to 900 captured civilians had been killed . At a spot called " El Calabozo " ( " The Dungeon " ) , the battalion surrounded the IDPs and opened fire at close range . The soldiers threw some of the bodies into the river and reportedly threw acid on others , making an exact death toll impossible to confirm , but more than two hundred were reported missing after the incident by surviving family members . The dead included infants and elderly
El Mozote massacre
El Mozote massacre
El Calabozo massacre