Jian-Yun “John” Dong left what he called a suppressive government in China and never intended to return when he traveled to the United States to study in the 1980s.

The 56-year-old kept his composure Thursday as he told a jury in a federal courtroom in Charleston that, as an “intellectual,” he had been persecuted in the country and even arrested once and beaten by Chinese police.

But Dong began to cry when he spoke of two things: his now-estranged wife and the breakdown of the company that he leads, the biotechnology firm based in Mount Pleasant called GenPhar.

Dong told the jury when he left China, he had only been married one week to Danher Wang and that he missed his wife while he studied at the University of Alabama-Birmingham. Wang later would join Dong in the United States and the pair later would move to Charleston.

Wang, 53, showed little emotion in that same witness stand on Wednesday when she admitted to her alleged role in an illegal campaign contribution scheme with Dong. She told the jury that she didn’t know what she was doing was illegal but that she should have asked more questions. Wang pleaded guilty last week and agreed to testify against Dong.

Dong also is accused in that alleged plot, charged with conspiring to funnel money through proxies to U.S. Sen. Lindsey Graham and his political action committee. Dong also is accused of lying to investigators and witness tampering.

Graham is not accused of any wrongdoing, and prosecutors said he and members of his staff were not aware the contributions were tainted.

Dong also told the jury he did not know what he was doing was illegal. He repeatedly referred to the campaign contributions as a “privilege.” Dong fought back tears as he told a jury that his “stupid mistake” cost the jobs of GenPhar employees and led to the loss of federal projects, he said. “I would never jeopardize the interest of the company,” Dong said.

The company is still afloat, he said, with three employees including himself, Wang and another employee, but it’s a long way from its once 20-plus employees. GenPhar was developing vaccines for the Ebola and Marburg viruses, Dong said.

Prosecutors have said that Dong convinced former employees to serve as proxies for his donations because he had reached the maximum limit of contributions he could make to Graham.

Dong believed contributions to Graham would lead to more federal funds through grants and earmarks for GenPhar, prosecutors said.

Dong told the jury that wasn’t true and said he donated to Graham because he wanted to support a leader with whom he shared similar beliefs. “I was only interested in Graham being re-elected,” he said.

Dong’s attorneys indicated he would be the only witness they’d call during the week-long trial. His testimony wrapped up Thursday afternoon.

Throughout the week, prosecutors called several witnesses to testify, including former employees of GenPhar who said Dong asked them to make contributions to Graham that he and Wang later would reimburse. Several people also told the jury they advised Dong that conduit contributions were illegal.

The jury likely will begin deliberating this afternoon.