The video, shot during federal investigators' interrogation of nanoscientist Charles Lieber, was played for jurors during the Friday court hearing, the fourth day of the trial on Lieber's alleged false statements about China funding.

The 62-year-old Harvard professor had maintained that he didn't take payments from a Chinese university except for compensation of his travel costs to China. But he shifted account quickly after Federal Bureau of Investigation (FBI) agents Robert Plumb and Kara Spice accosted him with copies of evidence, including a bilingual contract he signed with the Wuhan University of Technology (WUT) in 2011.

"That's pretty damning," Lieber, dressed in a blue jacket, told the agents at the campus police station during a three-hour interrogation, which took place on the day of Lieber's arrest nearly two years ago. "Now that you bring it up, yes, I do remember," he said in the recording, local media reported.

The five-year agreement described Lieber as a "strategic scientist" at the Chinese school that entitled him to $50,000 per month with approximately $158,000 in living expenses. It also alluded to his future involvement with China's Thousand Talents Plan, a state-run program to solicit top scientific and specialized experts from around the world.

Later in the interview, FBI agents showed Lieber an email he wrote, asking the Wuhan university to pay half of his salary in cash with the other half deposited into a Chinese bank account.

"I can't even believe I did this," Lieber said in response, local media reported. "It's my mistake and obviously I made a mistake."