The U.S. Department of Justice has filed charges against Chinese wind turbine manufacturer Sinovel Wind Group Co. Ltd. for stealing trade secrets from American engineering company AMSC.

According to a grand jury indictment brought in the U.S. District Court for the Western District of Wisconsin, Sinovel stole from AMSC a software source code that regulated the flow of electricity from wind turbines to electrical grids. The Chinese company had originally agreed to purchase software and products from AMSC but ceased after the alleged theft, costing the American company as much as $800 million in revenues.

Prosecutors say two China-based Sinovel executives—deputy research and development director Su Liying and technology manager Zhao Haichun—recruited Austria-based AMSC engineer Dejan Karabasevic to download the software from an AMSC computer located in Wisconsin.