Liu had downloaded the data found on his computer without his company's knowledge, was presenting at the conference without permission, and had told a co-worker that he was vacationing in Chicago, court records state.

The U.S. Department of Justice described Liu's presentation at the 4th Annual Workshop on Innovation and Commercialization of Micro & Nanotechnology as a "presentation sponsored by the Chinese government." But according to William Parker, founder of biotechnology company Creative MicroSystems Corp., who spoke at the conference in 2009, the event is a legitimate international forum for international researchers, designed to advance understanding of specific aspects of nanotechnology.

In an interview Tuesday, Parker said he was not familiar with Liu's work but was surprised to hear that he went ahead without company approval. "Usually, you have to get clearance to do a talk like this," he said.

Although much of the material on the conference's website was unavailable Tuesday, indicates that the November 2010 event was sponsored by a number of universities and government and scientific agencies, including China's Ministry of Science and Technology.

Liu had spoken at the conference more than once. He was a co-chairman of the event in 2009 and gave a talk entitled "Micro-Navigator for Spacecraft with MEMS Technology" at that year's event. He had been working for L-3 Communications for about seven months at the time of the 2009 workshop.