Three questions Bill Gates could face as he testifies to Congress on Epstein

The lead Democrat on the committee, Robert Garcia, told reporters on Monday: "Bill Gates was still communicating with Jeffrey Epstein, even after some of this kind of horrific information about him and what he was doing was public to a lot of folks, and so we want to ask Mr Gates, why continue that relationship?

"Who else did he see? What else might he know? And who else should we be bringing in to ask questions of?"

Gates told staff at his foundation in February that he said he was aware of some "18-month thing" that had limited Epstein's travel, but that he didn't properly check his background.

That account is likely to be tested in questioning by the committee.

Lawmakers are expected to probe how plausible it is that Gates – one of the titans of the information sphere - would have remained largely incurious about the details of Epstein's background, including facts that were already in the public domain, during a period when the two men appeared to spend significant time together.

In its letter inviting Gates to sit for an interview, the committee said it believed he would have useful information concerning the "ways in which Mr Epstein and Ms Maxwell sought to curry favor and exercise influence to protect their illegal activities".

This at least is a possible reason for Epstein wanting to know someone like Gates - who, while not a politician, is a global figure with significant networks and influence.

The committee's point here suggests that Epstein wasn't just looking for powerful friends, but also ways of leveraging those contacts for other, illicit reasons.

It's clear Epstein appeared to spend a lot of time cultivating such people. His associations often blurred the line between business and social interactions.

He also kept copious and documented records of the people he knew: hence the piles of emails, photos and other documents that are now in the public domain.

He entertained, wined and dined, and flew people around for vacations at his various properties. It is plausible that some of the details he hoarded about his associates could have been used to pressure or influence them, though there is no evidence that this occurred in Gates's case.

Nonetheless, details about the alleged STI - denied by Gates - would certainly have the potential to be deeply embarrassing and damaging if Epstein had decided to use them.

"We want to know whether Epstein wanted to influence Gates or even whether he blackmailed Gates in any way like he allegedly did with others," Congressman Suhas Subramanyam, another Democrat on the committee, told the BBC.

From Gates's point of view, his stated motivation was raising money for his global health initiatives. Earlier this year, the Gates Foundation said: "On the basis of Epstein's claims that he could mobilise significant philanthropic resources for global health and development, a small number of foundation employees interacted with Epstein to try to secure this potential funding."

But, it added, "ultimately, the foundation did not pursue any collaboration with Epstein and no fund was ever created". It went on to say that it "regrets having any employees interact with Epstein in any way".

So it comes down to this: why spend so much time with someone who wasn't delivering? That will most certainly be a central question on the lips of those who will get to quiz Gates.

Additional reporting by Cai Pigliucci and Daniel Wittenberg