If USA still want him, US aootney can send him a supeona
and Deprtmant of State has to give him a visa for him
to come to US court (There is such a visa so I heard).

If he refuse to answer the supeana, USA can not do anything because there is no extradiction treaty betwen USA and China otherwise Zhang Wuchang (Steven Cheng sp?)who is Hong Kong economist will be arrested by Chinese police and sent back to USA because he is till wanted by FBI