Lawyers for two employees of a Chinese biotechnology company accused of stealing patented seed corn from companies in the United States are fighting the U.S. government's use of laws established to fight terrorism and espionage to gather evidence against them.

Mo Hailong and his sister Mo Yun, who were born in China, are among seven people charged with conspiracy to steal trade secrets. They face a September trial in Des Moines. The other five haven't been located.

Federal court documents say FBI agents used the Foreign Intelligence Surveillance Act to secretly place GPS monitors and recording devices in rental cars, tap cellphones, and capture computer files.

Mo Hailong's attorney, in documents filed Wednesday, asks the court to force the government to disclose covert surveillance techniques used and identify evidence gathered.