A professor at the University of Arkansas specializing in electrical engineering has been arrested by the FBI and charged with wire fraud after being accused of failing to tell federal authorities about his jobs and payments from Chinese companies, authorities announced Monday.

Simon Ang “had close ties with the Chinese government and Chinese companies, and failed to disclose those ties when required to do so in order to receive grant money from NASA,” according to a criminal complaint filed against him. Ang was arrested Friday, and court papers were unsealed Monday. A lawyer for Ang declined to comment.

The case marks the latest strike by the Justice Department against what national security officials say is a problem at some American universities: professors and researchers hiding their financial and professional arrangements with Chinese entities, in violation of ethics rules for federal grant money.

In January, the FBI arrested the chair of Harvard University’s chemistry department on charges that he lied about his work for a Chinese university. At the time, John Demers, the head of the Justice Department’s national security division, said American universities “should take this threat seriously and continue to take actions to confront it.”

Ang, 63, is the director of the High Density Electronics Center in the University of Arkansas’s department of electrical engineering. He has worked at the school for decades.

Since 2013, Ang’s work received more than $5 million in federal grant money from NASA and other agencies, according to the criminal complaint filed against him.

Officials said the Ang investigation began when a university staffer examined a hard drive in the library’s lost-and-found bin, trying to see whether they could identify the device’s owner.

The drive contained emails apparently from Ang, including one that said “there are things that are becoming very difficult for me recently because of the political climate. You can search the Chinese website regarding what the US will do to Thousand Talent Scholars. Not many people here know I am one of them but if this leaks out, my job here will be in deep troubles. I have to be very careful or else I may be out of my job from this university.”

China runs a number of “talent” programs, designed to attract accomplished scientists and experts from around the world to provide expertise to China’s own research and development programs.

The criminal complaint filed against Ang charges that the professor in 2014 disclosed to the University of Arkansas his participation in China’s “Thousand Talent Scholars” program but did not reveal his involvement in other such programs from 2012 to 2018.

“Ang obviously knew about the requirement to disclose such conflicts of interest and deliberately kept all such conflicts of interest from the University of Arkansas and NASA,” the complaint said.

A University of Arkansas spokeswoman said Ang “has been suspended without pay from his responsibilities at the university and the university is actively cooperating with federal authorities in the investigation.”