Jìzhě zhuīgēnsùyuán, zhōngyú chá qīng le shìjiàn de zhēnxiàng.
The reporter dug down to the source and finally uncovered the truth of the incident.
Tips
usage
Near-synonym of 追本溯源; 追根溯源 is slightly more common in modern journalism. Often used as a sentence-opening adverbial: 追根溯源,... (tracing it back, ...).
memory
根 (root) and 源 (source) are the literal endpoints; 追 (pursue) and 溯 (go upstream) are the verbs. Literally 'pursue the root, go upstream to the source'.