run someone/something to ground idiom (UK also run someone/something to earth)
经过艰难调查而发现；经过艰苦努力而搜寻到
to find someone or something after a lot of searching and problems
Detectives finally ran the terrorists to ground in an apartment building in Chicago. 侦探们历尽艰辛终于在芝加哥的一座公寓楼内挖出了恐怖分子。