Su Bin, a Chinese national in his late 40s, has been indicted for allegedly directing two China-based hackers to infiltrate Boeing and other defense contractors to steal gigabytes of documents describing U.S. military aircraft.

He was arrested in Canada in June.

According to the indictment, Su allegedly worked with two unnamed and unindicted co-conspirators between 2009 and 2013 to obtain documents related to planes such as the C-17, a cargo aircraft, and the F-22 and F-35 fighter jets.

According to the indictment, free email services were part of what brought the conspiracy down. Email from one of the China-based hackers to the other one describes a painstaking, year-long 2.7 million yuan ($439,000) effort that successfully stole 85 GB of information about the C-17, including electronic cable wiring documents and detailed schematics in August 2012.

The hacker wrote that Boeing’s network is “extremely complex." The company has layers of security equipment including firewalls and intrusion detection and prevention systems.