jì zhě / yán zhe / zhè tiáo / xiàn suǒ / páo gēn jiū dǐ / zhōng yú / chá qīng / le / wèn tí / bèi hòu / de / lì yì / guān xì

记者沿着这条线索刨根究底，终于查清了问题背后的利益关系。

The journalist investigated the lead thoroughly and finally uncovered the vested interests behind the problem.