A Chinese businessman has been charged with stealing military project data from Boeing and other U.S. firms with defense contracts and selling it to China.

Su Bin was arrested in June in Canada, where he operates an aviation technology company, while trying to get Canadian citizenship, according to the BBC.

The U.S. first accused China of spying in 2013, which Chinese officials said was baseless and a threat to the relationship between the two countries, according to the BBC.

But in June, Bin and two others were arrested in connection with the spying allegations.

Bin allegedly tried to sell the data to state-owned firms in China.

The Justice Department said it remains "deeply concerned about cyber-enabled theft of sensitive information."

In May, the U.S. accused five Chinese military officials of hacking into five companies that specialize in "solar panels, metals and next-generation nuclear power plans," according to Bloomberg.

David Hickton, U.S. attorney for the Western District of Pennsylvania, home to four of those five companies' headquarters or main offices, said the stolen data potentially costs billions of dollars in lost research and development to the companies hacked and is equivalent to the loss of jobs.

The U.S. has been aware of Chinese spying since as early as 2002, and foreigners aren't the only ones selling information to China.

On Thursday, Californian and naturalized citizen Walter Liew, 56, was fined $28 million and sentenced to 15 years in prison for selling information about a key product for DuPont -- titanium dioxide -- to China, according to The Huffington Post.

Though no cases directly involve the Chinese government, the U.S. has accused the Chinese of "systematically stealing American high-tech data," according to BBC.

"Success in the global marketplace should be based solely on a company's ability to innovate and compete, not on a sponsor government's ability to spy and steal business secrets," Holder said. Bloomberg reported that Holder emphasized "that U.S. surveillance and spying is not used for commercial purposes."