Yesterday, federal prosecutors unsealed a new indictment against former Trump campaign manager Paul Manafort. The indictment contains new evidence that Manafort hid millions of dollars in overseas income from US authorities, and it charges Manafort and his associate Richard Gates with numerous counts of tax and bank fraud.

The indictment also suggests that Manafort's lack of technology savvy helped prosecutors build a case against Manafort and Gates. The pair allegedly submitted a variety of fraudulent documents to lenders in order to borrow money against properties purchased with overseas funds—funds that were never reported to the IRS. One reason prosecutors were able to build a paper trail against the pair: Manafort needed Gates's help to convert a PDF document to Word format and back again.

In 2016, Manafort allegedly wanted to create a fake profit-and-loss statement for his company, Davis Manafort Partners, in order to inflate his income and qualify for a loan.

"Manafort emailed Gates a .pdf version of the real 2016 DMI P&L, which showed a loss of more than $600,000," the indictment claims. "Gates converted that .pdf into a Word document so that it could be edited, which Gates sent back to Manafort. Manafort altered the Word document by adding more than $3.5 million in income."

Then, according to the indictment, Manafort "sent this falsified P&L to Gates and asked that the Word document be converted back to a .pdf, which Gates did and returned to Manafort."

By sending these documents back and forth by email, Manafort and Gates made it easy for prosecutors to pinpoint exactly who changed the documents and when.

In another incident earlier that same year, Manafort allegedly submitted another fraudulent profit-and-loss statement to a different lender with his firm's income inflated by $2 million. An employee at this lender, who was apparently aware of Manafort's ruse, replied back, "Looks Dr'd. Can someone just do a clean excel doc and pdf to me?"

"A subsequent version was submitted to the bank," the indictment says.