Disappearing Witnesses

They may not have ever existed at all. Go figure.

Ms. Leung, a donor and fund-raiser for political candidates in California, also played an important role in the investigation of Chinese donations to the Clinton-Gore campaign. A former senior official in the Justice Department said that if Ms. Leung was a double agent, she might have compromised the entire campaign finance investigation. "It raises questions about whether the Chinese knew the details about the whole finance investigation even before Congress or Janet Reno knew them," the official said, referring to the former attorney general in the Clinton administration.

A former prosecutor who was active in the case said several important figures in the investigation whom authorities sought to subpoena disappeared before they could testify. "There were people we never found," the prosecutor said. "There were dead ends. Whether those were legitimate dead ends or artificial dead ends, we don't know."