Si Lili told Fan Xian the truth.

The truth behind Fan Xian's investigation of Si Lili was that Si Lili had told Fan Xian that the mastermind behind the Niulan Street assassination was Lin Gong. Fan Xian wanted to avenge Si Lili, but he also wanted to protect Lin Gong, because Lin Gong was the second brother of Fan Xian's fiancée, Lin Wan 'er. In order to protect Lin Gong's safety, Si Lili would rather be tortured than betray Fan Xian. Fan Xian finally learned the truth and avenged Si Lili.

The truth behind Fan Xian's investigation of Si Lili was that the mastermind behind the Niulan Street assassination was Lin Gong. Fan Xian used modern interrogation techniques to threaten and intimidate Si Lili, including telling her that her life and death were in his hands, threatening her with a lifetime of house arrest and dark loneliness as punishment, and throwing out a few deadly pills in an attempt to lure her into taking them. Under Fan Xian's threat, Si Lili compromised and told him the truth. However, Fan Xian's interrogation process was not described in detail in the search results provided.

In the 17th episode of " Celebrating Years," Si Lili told Fan Xian that Lin Gong was the one.

During the Qing years, Si Lili told Fan Xian that the mastermind behind the scenes was Wu Bo 'an.

During the Qing years, Si Lili told Fan Xian that the mastermind behind the scenes was Wu Bo 'an.

The person Si Lili told Fan Xian was Lin Gong.

The person Si Lili told Fan Xian was Lin Gong.

The person Si Lili told Fan Xian was Lin Gong.

The person Si Lili told Fan Xian was Lin Gong.

The person Si Lili told Fan Xian was Lin Gong.