Collocations for atrocity - noun

appalling (esp. BrE), terrible, worst
one of the worst atrocities of the war

alleged
human rights
terrorist

be responsible for, carry out, commit, perpetrate
In the war, both sides committed atrocities.

occur, take place

stories

atrocity against
atrocities against the civilian population

atrocity by
reports of atrocities by gunmen

accounts of atrocities, allegations of atrocities, reports of atrocities