Mr. Mitnick, 80, now semiretired and living in Florida, said that while he no longer had access to Mr. Trump’s original returns, the documents appeared to be authentic copies of portions of Mr. Trump’s 1995 tax returns. Mr. Mitnick said the signature on the tax preparer line of the New Jersey tax form was his, and he readily explained an obvious anomaly in the way especially large numbers appeared on the New York tax document.





A flaw in the tax software program he used at the time prevented him from being able to print a nine-figure loss on Mr. Trump’s New York return, he said. So, for example, the loss of “-915,729,293” on Line 18 of the return printed out as “5,729,293.” As a result, Mr. Mitnick recalled, he had to use his typewriter to manually add the “-91,” thus explaining why the first two digits appeared to be in a different font and were slightly misaligned from the following seven digits.





“This is legit,” he said, stabbing a finger into the document.