‘His own tax lawyer testified against him’: Trump biographer David Cay Johnston explains why Trump is terrified of his taxes
Journalist David Cay Johnston is the founder of DCreport.org (screengrab)

Pulitzer Prize-winning journalist David Cay Johnston explained the two main reasons President Donald Trump is terrified of his tax returns.

Johnston laid out his theory during in an interview on MSNBC's "Hardball" with Chris Matthews.

The host noted Johnston's recent article pointing out that Treasury Secretary Steve Mnuchin could go to prison for five years for not turning over Trump's tax returns to the House Ways and Means Committee chair.

"David, tell us what you can about -- based upon your having seen one of Trump's tax returns, I think it was 2005, what is he most sensitive to about people like us knowing ... what does he want to keep secret?" Matthews asked.

"Well, Chris, there isn't now and there never has been any evidence, verifiable evidence, Donald is a billionaire. He's not a billionaire," Johnston replied. "That's one thing he's worried about."

Johnston is the author of the 2016 book The Making of Donald Trump and the 2018 book It's Even Worse Than You Think; What the Trump Administration is Doing to America.

"Secondly, he's worried that an audit will show tax cheating," he continued.

"Let's not forget, Donald was tried twice for tax fraud, civil tax fraud, and was found in both cases to have engaged in fraud," he reminded. "He was excoriated by the judges in both cases."

"His own tax lawyer testified against him," he continued. "His tax lawyer said, 'That's my signature on the tax return, but I did not prepare that tax return.' That's a very strong badge of fraud."

"And you notice that his sister, Maryann Trump Barry, as soon as she came under investigation by judicial authorities, because she's a federal judge, as a tax cheat, resigned," he added.