When journalist David Cay Johnston first laid eyes on two pages of U.S. President Donald’s Trump 2005 federal tax returns that showed up in his mailbox, his first thought was that the document came from Trump himself.

But Johnston, founder and editor of the non-profit DCReport.org, told CTV News Channel Thursday that he no longer believes Trump leaked the returns.

There has been plenty of speculation that the leak came from Trump as a means to distract from the growing scrutiny around his administration’s links to powerful forces in Russia. After all, the tax returns showed nothing damaging to Trump but his refusal to release his returns – a sharp break with precedent for presidents – has been ongoing fodder for his opponents.

“Well Donald has a long history of leaking information about himself. I suspect he was the source of the three pages of state tax returns that got out last fall because he didn’t complain about them,” says Johnston, who wrote a book called The Making of Donald Trump that points to many instances when Trump leaked information about himself or posed as his own publicist in order to plant stories.

The tax returns posted by DCreport.org and then talked about on MSNBC’s Rachel Maddow Show on Tuesday are client copies, not signed copies that would have been submitted to the Internal Revenue Service. And Johnston also says Trump has Johnston’s home address and telephone number.

The White House was swift to issue a statement verifying the authenticity of the returns, which showed Trump paid $38 million in federal taxes on $150 million in revenue, but railing against their release.

“The White House then did something utterly unethical. They gave this information to other journalists before we went up at DC Report. No White House back to Nixon that I dealt with, no corporation has ever done that,” said Johnston, a veteran investigative journalist and Pulitzer Prize winner.

Johnston says that shows Trump’s anger. The president then lashed out on Twitter, saying nobody had heard of Johnston. The two pages got under Donald’s skin “and when you get under Donald’s skin, which you can do by ridiculing him or showing him he’s not in control of something, his behaviour is erratic and sometimes bizarre.”

Johnston says since revealing the tax returns, his wife and grown daughter have been threatened.

“We don’t intimidate but I did think we should make a record … Donald (Trump) has literally during the campaign encouraged violence against those who do not fall in line with his dictatorial view of the presidency.”

Johnston says Trump is clearly angered by the obstacles blocking his policies, including his travel ban, because he has a distorted view of the powers of the Oval Office.

“Donald has no idea. He thinks judges are supposed to bend to his will the way judges do in totalitarian and authoritarian states.”

Johnston says he’s concerned that many Americans feel powerless and have forgotten that the government and the constitution belong to the people.

But that doesn’t mean that Trump’s support should be underestimated. In fact, Johnston believes Trump has more Americans lined up behind him now than when he took office two months ago. He doesn’t think that will last.

“Over time, Donald’s immaturity, his deep emotional and mental problems, his absolute lack of management skill and knowledge of the world are going to create more and more problems.”