C447 Both mother and child analyze the murderer together

Li Xiang asked Ye Min to contact the international public security officials to investigate about Zhao Qiming. The results were very consistent with what he knew, but the name of Zhao Qiming's mother that was written on the column said something unknown, which made Li Xiang feel that it was strange.

Why was it unknown? Could it be that Zhao Qiming's mother wasn't registered when he went overseas