caught red-handed就是现行犯正在作案，被现场捕获，当场被捕的意思。

【例句】
My boyfriend and I robbed a store and were caught red-handed.
我和男朋友去抢劫一家商店，被当场逮到了。

A thief was caught red-handed in the act of breaking open alock.
一个窃贼在砸开锁时被当场抓获。