Gallen, Switzerland, said in a statement at the time of the plea that it had cooperated with the probe "within the bounds allowed for by Swiss law" since learning that it was under U.S. investigation.

WSJ: Authorities: NY judge opens door to Swiss records

At the time of his death, he was allowed to travel within China, but was barred from leaving the country, the Associated Press news agency reports.

BBC: Belgian art dealer convicted of smuggling in China dies