Technicians used DNA technology to identify the suspect as a member of the Gu family, and Tao Weizhi embarked on a long investigative journey.For six years, he traveled all over the country, just to track down the Gu family. He was almost obsessed. Whenever he heard any information related to Donglin or the Gu family, he would delve into it in depth.Although Yang Wei and Cheng Shufeng persuaded him to give up many times, Tao Weizhi remained persistent, and they had no choice but to accompany him around.

By chance, Tao Weizhi learned that Gu Wanli's descendants were in Shucheng, and immediately went there with Yang Wei and Cheng Shufeng.In the Qing Dynasty Legal History of Shucheng Library, they found clues that Gu Wanli fled to Shucheng from Huai County, Hedong City.Tao Weizhi came up with a plan and decided to go to Huai County to explore the descendants of other branches of the Gu family.He quickly contacted Su Chang and Cao Yang for help, but was dissuaded, saying that this was tantamount to finding a needle in a haystack and was costly.But Tao Weizhi was determined and vowed to seek justice for the parents of the deceased, otherwise he would not be able to feel at ease.He consulted historical materials and learned that there was a village called Gujiapo in Huai County, so he decided to go and explore it.

Although Yang Wei and Cheng Shufeng had no choice but to follow Tao Weizhi to Huai County.However, there is no Gu Jiapo in Huai County, and Tao Weizhi searched the county annals and found nothing.Unwilling to give up, he rode his bicycle alone to ask around.Huai County is mountainous and the villages are scattered, so he had no choice but to climb over the mountains and ridges. After many hardships, he finally found Gujiapo, which was hidden deep in the mountains.However, when Wang Ran and his colleagues came with testing equipment to conduct DNA tests on men of appropriate age, the results found no matches.Tao Weizhi's hope was once again frustrated. He screened out all the men of the right age named Gu in Huai County, and there were more than 14,000 of them.

Tao Weizhi was disheartened and prepared to leave Huai County.However, the night before leaving, he accidentally saw someone online claiming to have moved from Gujiapo to Pingcheng.Tao Weizhi immediately rushed to Pingcheng as if he had found a treasure, and unexpectedly obtained the Gu family genealogy.After he handed over the genealogy to Qin Chuan, Qin Chuan praised his persistence and advised him to go back and rest.

The next day, Qinchuan held a case analysis meeting and believed that the suspect was a local.Although Tao Weizhi had different opinions, Qin Chuan's analysis was very clear, so he had to remain silent.Tao Weizhi was depressed and drank alone to relieve his sorrow.Seeing this, Yang Wei and Cheng Shufeng also came to him to complain.Qin Chuan guessed Tao Weizhi's dissatisfaction, so he hosted a banquet for them and invited Sun Chang, Cao Yang and Liu Lin to accompany them.During the dinner, Qin Chuan comforted Tao Weizhi with his own experience. Tao Weizhi finally let go and promised to follow Qin Chuan's arrangements.