During the raid, several insurgents were killed and the leader was captured.

captured 是动词 capture 的过去分词形式，在句中表示被动。capture 由词根 capt（来自拉丁语 capere，意为"抓住"）和后缀 -ure（表示动作或结果）组成，意思是"捕获、抓获"。captured 表示"被抓获"的状态。