顺藤摸瓜

shùn téng mō guā

to follow the leads to the source

Character by character

顺shùn
follow

藤téng
vine

摸mō
feel for

瓜guā
melon

警方顺藤摸瓜，抓到了整个团伙。

Police followed the trail and caught the whole gang.

Tone: neutral.

Common in crime news and investigations.

Learn it in context

This idiom and thousands more are in Learn Chinese with Bao, with audio, pinyin and drills that make them stick.