A former engineer was arrested on federal charges alleging he stole trade secret technology that was developed by the U.S. government to detect nuclear missile launches and to track ballistic and hypersonic missiles, the Department of Justice announced Wednesday.

Chenguang Gong, 57, of San Jose, California, was arrested Tuesday morning and charged with theft of trade secrets, the DOJ said in a press release. Gong is a native of China and became a U.S. citizen in 2011, the DOJ said.

Gong appeared in court Wednesday and was released on $2.5 million bond with location monitoring and curfew, a spokesperson for the U.S. Attorney’s Office in Los Angeles said.

During that hearing, which took place in San Jose, he was represented by a deputy federal public defender. He was ordered to make a court appeared in Los Angeles by Feb. 20 and it remains unclear who will represent him in that hearing, the spokesperson said.

While briefly working at a Los Angeles-area research and development company — from March 30, 2023 to April 26, 2023— Gong allegedly transferred 3,600 files from his work laptop to personal storage devices, according to court documents. Some of these files were later discovered on devices taken from Gong’s temporary residence in Thousand Oaks, California, the DOJ said, citing an affidavit filed in support of the criminal complaint against Gong.

Gong transferred more than 1,800 files after he had already accepted a new job at a main competitor of the company on April 5, 2023, the DOJ said.

The files are said to include “blueprints for sophisticated infrared sensors designed for use in space-based systems to detect nuclear missile launches and track ballistic and hypersonic missiles, as well as blueprints for sensors designed to enable U.S. military aircraft to detect incoming heat-seeking missiles and take countermeasures, including by jamming the missiles’ infrared tracking ability,” according to the DOJ.

The company Gong worked for, listed as the “victim company” in the DOJ’s release and in court documents, and the U.S. government invested tens of millions of dollars a year for more than seven years to develop the technology Gong is accused of stealing, the DOJ said, citing the affidavit.

The DOJ added that it would be “damaging economically” for the company if competitors got their hands on the technology, and it would also be a danger to U.S. national security if obtained by “international actors.”

The information stolen by Gong was “among the victim company’s most important trade secrets worth hundreds of millions of dollars,” the DOJ said, citing court documents. Many of the stolen files were marked “[VICTIM COMPANY] PROPRIETARY,” “FOR OFFICIAL USE ONLY,” “PROPRIETARY INFORMATION,” and “EXPORT CONTROLLED.”

“We will do everything to protect our nation’s security, including from foreign threats,” said United States Attorney Martin Estrada.

Estrada said that Gong had previously tried to provide China with information to aid its military and “stole sensitive and confidential information related to detecting nuclear missile launches and tracking ballistic and hypersonic missiles.”

“We know that foreign actors, including the (People’s Republic of China), are actively seeking to steal our technology, but we will remain vigilant against this threat by safeguarding the innovations of American businesses and researchers,” Estrada said.

While investigating Gong, the DOJ said the FBI found he applied a number of times to “Talent Programs” run by China from 2014 to 2022, all while employed by major U.S. tech companies.

The programs identify people who don’t live in China but have skills, abilities and knowledge that would aid the country’s economy and military, the DOJ said.

A 2014 application submitted by Gong revealed a plan to create products similar to those produced by the company he worked for at the time, the DOJ said. The FBI uncovered hundreds of confidential documents from that company in executing a May 8, 2023, search warrant, the justice department added.

Gong made a similar proposal in a 2020 application and traveled to China multiple times in search of funding for his proposals, which he continued to seek until March 2022, the DOJ said.

In a 2019 email, the DOJ said, Gong acknowledged he “‘took a risk” by traveling to China to participate in the Talent Programs “‘because [he] worked for … an American military industry company’ and thought he could ‘do something’ to contribute to China’s ‘high-end military integrated circuits.'”

If convicted, he could face up to 10 years in federal prison.