捕虜（ほりょ）を虐殺（ぎゃくさつ）したのは残忍（ざんにん）な行為（こうい）だ。

The slaughter of the prisoners was a barbarous act.

彼（かれ）は敵（てき）に虐待（ぎゃくたい）された。

He was badly treated at the hands of his enemies.

彼（かれ）はひどい虐待（ぎゃくたい）を受（う）けた。

He was treated with great cruelty.

戦争（せんそう）中（なか）多（おお）くの残虐（ざんぎゃく）行為（こうい）が行（おこな）われた。

Many atrocities were committed during the war.