"順藤摸瓜"用英語怎麼說？

“順藤摸瓜”，漢語成語，字面意思是“順著瓜藤可以摸到瓜（follow the vine to get the melon）”，比喻按照某個線索查究事情，可以翻譯爲“track down somebody [something] by following clues”。

例句：

他們順藤摸瓜，終於找到了罪犯的下落。

They tracked the criminal down by following clues on his whereabouts.