A Chinese news dated October 7, 2017 reported -
"The police believe that Rong Xin jumped off the plane ahead of time before the crash . More than six months have passed, but Rong Xin's whereabouts are still unknown, and the police have not found his body. Last month, Rongxin's widow applied to the court for a ruling that he was dead so that his family can handle inheritance and insurance matters.
On October 5th, Judge Julia Owdziej of Washtenau County, Michigan, formally signed the decree announcing that 27-year-old Rong Xin had been killed in an airplane accident.
According to the data, Rong Xin is from Changchun, China . He graduated from Tsinghua University, China in 2011, majoring in automation, and then enrolled in the School of Information at the University of Michigan to pursue a doctorate degree in artificial intelligence and human-computer interaction."
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In the case of Japanese, for example, they do not give up searching for their family member(s) for a few years before giving up.
Is 6 month enough in the US?
Source:
跳飞机失踪华裔博士 正式被宣布死亡(图) - 美国社会 -