Lieber, the 62-year-old ex-chair of Harvard’s department of chemistry and chemical biology, was accused of hiding his involvement in China’s Thousand Talents Plan, which recruits people from foreign countries who are able to share secrets about their country’s technologies and intellectual properties.

Prosecutors said Lieber organized conferences, published articles, and applied for patents on the behalf of Wuhan University of Technology. In return, the university paid him $50,000 a month. Lieber also reportedly earned over $1.5 million in grants and as much as $158,000 for living costs. Authorities added that Lieber concealed all of this to preserve his reputation.

According to CNN, Lieber’s Harvard research group, which received more than $15 million in federal funding, required the disclosure of any foreign financial conflicts of interest.

Lieber was found guilty of two counts of filing false tax returns, two counts of making false statements, and two counts of not filing reports for his Chinese bank account.

On Wednesday, Chinese Foreign Ministry spokesperson Zhao Lijian said the U.S. should not “stigmatize” China’s scientific exchange programs, adding that the country’s programs follow similar guidelines to U.S. programs.

He said that the U.S. should “instead do something conducive to China-U.S. scientific and people-to-people exchanges and cooperation.”

Lieber had pleaded not guilty to the charges. Lieber’s defense attorney, Marc Mukasey, had argued that prosecutors lacked proof of the charges, maintaining that investigators kept no records of their interviews with Lieber prior to his arrest.

Lieber denied his involvement during inquiries from U.S. authorities, including the National Institutes of Health, which had provided him with millions of dollars in research funding, prosecutors said.

The case is among the highest profile to come from the U.S. Department of Justice’s “China Initiative.”

The effort, launched in 2018 to curb economic espionage from China, has faced criticism that it harms academic research and amounts to racial profiling of Chinese researchers.

Hundreds of faculty members at Stanford, Yale, Berkeley, Princeton, Temple and other prominent colleges have signed letters to U.S. Attorney General Merrick Garland calling on him to end the initiative.

The academics say the effort compromises the nation’s competitiveness in research and technology and has had a chilling effect on recruiting foreign scholars. The letters also complain the investigations have disproportionally targeted researchers of Chinese origin.

Lieber has been on paid administrative leave from Harvard since being arrested in January 2020.

The Associated Press contributed to this report.