里应外合 裡應外合

    lǐyìngwàihé

    1. Idiomto coordinate outside and inside offensives (idiom); to act together (figuratively)

    警察在外面包围,内线同时里应外合,最后抓住了逃犯。Jǐngchá zài wàimiàn bāowéi, nèixiàn tóngshí lǐyìngwàihé, zuìhòu zhuāzhùle táofàn.The police surrounded from the outside, while an insider coordinated from the inside, and in the end, the fugitive was captured.