There are still serious questions about how Hamas financed its deadly attack on Israel last weekend. We do know, however, that for years, Hamas has been collecting funds in cryptocurrency. Israeli and U.S. authorities have cracked down on this flow of funds in recent days.

Ari Redbord is a former federal prosecutor and U.S. Treasury Department official who’s now global head of policy at TRM Labs, a cryptocurrency compliance firm. He spoke with “Marketplace Morning Report” host David Brancaccio and the following is an edited transcript of their conversation.

David Brancaccio: Let’s start with some context. Hamas is subject to sanctions from the U.S. Treasury Department. So its access to the regular international banking system is supposed to be severely restricted. Is that part of the appeal, if you want to move money, is that you turn to crypto?

Ari Redbord: I think that’s right, in part. I think you have to understand that it’s a very small piece of sort of a much larger terrorist financing puzzle. But it’s certainly a piece. And part of that is very much because you can move funds outside of the traditional financial system.

Brancaccio: This is part of one of the reasons I wanted to talk to you. I have, in the past, often referred to crypto as “money laundering on a stick.” Bad actors can take advantage of this technology. But in the work that you do, I mean, you’re saying that crypto actually may make it easier for authorities to spot illegal use of money because the ledger can’t be forged.

Redbord: That’s right. You know, cryptocurrency moves on blockchains, which are essentially networks of computers. And most blockchains are open and traceable and transparent. And using tools like TRM, law enforcement and national security authorities and others, globally, are able to actually track and trace the flow of funds on blockchains to ultimately seize those funds back.

In 2020, the U.S. Department of Justice, FBI, IRS-CI, other law enforcement, seized about 150 cryptocurrency wallet addresses associated with Hamas, and then went ahead and took down the infrastructure, the websites, that Hamas was using to raise funds. So the ability to track and trace the flow of funds on blockchains is absolutely critical here, and something we really can’t do in the traditional world.

Brancaccio: Any of this public? Where the crypto donations are coming from that are headed to Hamas?

Redbord: It’s interesting. And I will say that that is a major focus for TRM, a major focus for our law enforcement partners globally. But look, Hamas was an early adopter of crypto. We go back to about 2019, and we saw Hamas soliciting crypto donations in Bitcoin on telegram channels, then move to soliciting donations on their website. To answer your question, what we’ve seen over the last few days is really sort of a pretty disparate fundraising effort for those who are supporters of Hamas. And we’re continuing to track that, the inflows, the outflows, where those funds are coming from. And we’ll see. Obviously, a real focus on Iran and trying to understand financial flows from Iran to Hamas at this point, and that’s an ongoing process.

Brancaccio: I think it was April of this year, Hamas announced it would no longer take donations in bitcoin. Perhaps it’s because of its traceability?

Redbord: Yeah, really important point. And that’s essentially what Hamas itself said that, you know, law enforcement and other authorities have been coming down on their supporters because they’ve been able to trace and track these flows. And announced in April that they would not be soliciting donations in cryptocurrency. Now, whether that’s entirely true or not, it’s hard to say. We’re obviously seeing at least supporters of Hamas go out there raising funds in crypto.