A big story in Sunday’s Washington Post lays out in detail how Donald Trump’s business, in the years before Trump became president, went on what the newspaper describes as a “buying binge,” purchasing property and extending the reach of the brand. What’s most surprising, however, is that much of this—at least $400 million worth—was done in cash. Not only was it a surprising strategy for someone who famously—and infamously—used to go into debt to make purchases; it also raises the question of exactly where the cash came from. And, indeed, this question may be of interest to federal investigators.

The Post article was written by three reporters: Jonathan O’Connell, Jack Gillum, and David A. Fahrenthold. After its publication, I spoke by phone with Fahrenthold, who won a Pulitzer Prize last year for his coverage of Trump’s charitable work. (He also broke the story of the Access Hollywood tape.) During the course of our conversation, which has been edited and condensed for clarity, we discussed how the Post came upon this story, what makes the Trump business so unusual, and where reporting on Trump’s finances goes from here.

Isaac Chotiner: What was it that led you to look into the Trump Organization’s use of cash, and why hadn’t it been extensively reported on more?

David A. Fahrenthold: The Trump Organization is a really unusual business that has its arms in a lot of different things, and it is opaque from the outside. So, we have been trying to understand pieces of it as we went along. Our resolution for this year was to understand the debt of the Trump Organization. There are some really mysterious things I don’t understand about his debt. The Great White Whale of this reporting is something called Chicago Unit Acquisition LLC, which is this odd LLC that Trump has listed on his personal financial disclosures. It’s like a shell company that he himself owns and yet he claims it has no assets. And yet he says that he owes that shell company more than $50 million. I don’t know anything about that.

So, I got started looking at: Who are his debts? Who does he owe money to? And I thought the way to do that comprehensively would be to pull the land records for everything I knew he owned, and try to see what mortgages were on the deeds. Who owned the mortgages? How old were they? What rates were they for? And I thought I might find mortgages he hadn’t accounted for in his personal financial disclosures. Instead I found a bunch of places with no debt at all. And when we figured that out, especially in places like Scotland and Ireland, where there is tons of money going in with no loan, that’s what made us say: OK, maybe that’s the story—this odd buying pattern that doesn’t comport with how other people do it.

When did Trump switch over to using cash on a lot of these deals, rather than debt, and do you have any sense of what sparked the change?

The first one of these big purchases that he makes in all cash, at least the first one I know of, is in 2006, when he buys an estate in Scotland that he turns into a golf course later. Maybe there are other all-cash purchases before that, but I haven’t found any.

The answers for why, then: The Eric Trump answer is that the Trump children were coming up into the business and were less desirous of risk than their father was. Their father remembered his debt years ago, and so they just decided to buy things in cash. The guy who worked with Trump to buy that estate thought it was some sort of mystical connection. Trump’s mother was from Scotland and so maybe he wanted to own this piece of Scotland outright. Those are the only concrete explanations I have uncovered.

What was the state of Trump’s business empire in 2006?

Around that time, the first wave of The Apprentice has sort of crested and The Apprentice’s ratings are declining. I think it was before they had figured out how to boost them again with Celebrity Apprentice. That year, 2006, is sort of significant because it is the year of Trump’s life when he is spending a lot of time in Los Angeles. They are trying to boost the ratings by having it in Beverly Hills; he is sort of at loose ends in Los Angeles. Melania has just had Barron back in New York. He meets Stormy Daniels that year. It’s a year of a lot of change and upheaval in his personal life.

Businesswise, it’s a period when he starts getting into these partnerships, and you have these licensed properties in the U.S. and overseas: Felix Sater, Bayrock, Trump Panama, licensed properties that Trump puts his name on but doesn’t own, and that later come under a lot of scrutiny.

Deutsche Bank, as you report, was really the only major lender offering him loans after his bankruptcies. Why were they willing to do so, and why weren’t others, especially as he became a bigger celebrity and more “respectable” in the later part of the last decade?

Deutsche Bank is not a world I know well. There is a particular banker on the Deutsche Bank private wealth side who seems to be his main lender. It’s not the main part of Deutsche Bank that would normally give this size of commercial loans. The only other big financial institution that has big loans out to him is something called Ladder Capital Finance. They are involved in a lot of the older debt that has been refinanced on a lot of Trump’s New York buildings. One connection there seems to be that the son of Trump’s CFO works at Ladder Capital Finance. At Deutsche there is not an obvious nexus like that, but they were lending to him when nobody else was.

Most people in the real estate business seem to believe paying cash isn’t the best way to make deals, which raises the question of why he was doing this. And, if he had $400 million in cash during this period, that’s a bit of a security blanket for a bank who might lend to him. How do you understand that contradiction?

It certainly seems to be a contradiction, as you said. For most people, if you had $400 million, you wouldn’t just sink it all into golf courses, which are notorious as not-great moneymakers. You would use it as leverage to get more loans, or things with a greater rate of return, especially if you had $400 million in the period after the great recession, 2008–2009. You would be in a position to buy a lot of assets—real money-making assets—really cheaply. The only explanation we have gotten from the Trumps is from Eric, who said they were changing the business, and that it wouldn’t be a traditional big borrow, big risk, big reward real estate business anymore. Instead it’s like a generational business. We are going to buy these assets and we are going to produce a cash return and live off it, and we aren’t going to be the wheeler dealers of years passed.

But even that explanation has its own contradictions, because they do take on two really risky, really large transactions with debt, both with Deutsche Bank: the Doral golf course in Florida, and the old Post Office hotel in D.C. Those are both really old-style Trump deals with a lot of debt and a lot of risk.

Is this traditionally a warning sign for lenders—putting down all cash on deals this big?

I don’t know. We have talked to people in the golf financing industry who say it just doesn’t happen on this scale. Usually, the only people who would put this much money—their own cash—into golf course transactions would be people who basically had so much money that they didn’t need to make money work for them. Imagine, like, the sovereign wealth fund of Abu Dhabi, or the sovereign wealth fund of Norway. They just wanted to diversify their assets and make money someplace. No matter how well he was doing, I don’t think Trump was on the same scale as the sovereign wealth fun of Abu Dhabi. What I’m saying is that I don’t think that lenders have a lot of experience with people who are buying huge things in cash.

Was Michael Cohen involved in any of these deals, and in your reporting did you come across anything suggesting that these cash deals had caught the interest of any of the investigations swirling around Trump and his associates?

Second question first: No. Not that I have a lot of great visibility [into] what Robert Mueller’s doing, but I did not come across any evidence that this is part of anybody’s investigation. As far as Cohen, the way we looked for his involvement in these things was to look at both the sale documents—which Trump lawyers signed the deed of sale—but also the corporation documents. These things are all bought through LLCs, so which Trump lawyers signed off on the LLCs that were created to buy the properties. The only one that Michael Cohen was involved in was in this property at 806 North Rodeo Dr. in Beverly Hills, which [Trump] buys for all cash for like 10 million in 2007, and sells next year at a loss.

What do you think are the biggest unanswered questions about your story?

I guess two things. One would be: Have I seen the whole universe? Are there other all-cash transactions out there that I haven’t found. And No. 2 is: What was their cash flow? Eric Trump has said that their existing properties were throwing off so much money that it wasn’t a big deal to dip into them to buy an $80 million golf course, in the case of Turnberry [in Scotland]. Nothing that I have seen from the outside indicates that they have that level of liquidity, but I haven’t seen very much from the outside. The next question is about the sources of their cash flow from this period, and where their cash was coming from. That would help us understand a little bit more the context around Eric’s explanation.