The Washington Post’s Rosalind S. Helderman and Tom Hamburger are out with a must-read reconstruction of the Aug. 2, 2016, meeting between Paul Manafort and his associate in Ukraine, Konstantin Kilimnik. This is the increasingly intriguing meeting that special counsel Robert S. Mueller III has zeroed in on in his Russia collusion probe, according to court documents.

And at the end, they include a new and noteworthy denial from Oleg Deripaska, the Russian oligarch whose ties to Russian President Vladimir Putin and Manafort have put him at the center of it all.

“We can confirm that Mr. Deripaska has never lent his private jet to Mr. Kilimnik, nor has ever had any interaction with him,” Deripaska spokeswoman Larissa Belyaeva said.

Some media reports have suggested that Deripaska might have lent his personal jet to Kilimnik around the time of the Aug. 2 meeting in New York. Flight records show it landed in Newark shortly after midnight on Aug. 3 and took off a few hours later. Deripaska’s team has denied that part before.

What’s new here, though, is the second part of the denial: Deripaska saying he has never even spoken with Kilimnik.

That’s significant because Kilimnik was reported to have been a liaison between Manafort and Deripaska. There have even been suggestions that Kilimnik might have met with Deripaska shortly before his meeting with Manafort on Aug. 2.

In a July 29, 2016, email from Kilimnik to Manafort, which was first reported by The Post in 2017 and detailed further by the Atlantic, Kilimnik says he met that day “with the guy who gave you your biggest black caviar jar several years ago.” He says he spoke with him for “5 hours” and that “I have several important messages from him to you.”

Congressional investigators thought this coded reference was probably Deripaska, who is referred to in earlier Kilimnik emails as someone from whom Manafort hoped to recover debts. And the idea that Kilimnik would be meeting with Deripaska on July 29 and possibly passing things on to the Trump’s campaign chairman on Aug. 2 — in the thick of the 2016 campaign — would seem problematic, at best.

Deripaska, though, has now completely denied that he ever met with Kilimnik. It’s possible that he’s lying, but a five-hour meeting between Kilimnik and a huge Russian tycoon is potentially something Mueller’s team could find out about — especially on a specific date.

Let’s assume for a moment that this denial is accurate — that Kilimnik wasn’t referring in his July 29 email to meeting with Deripaska, but rather someone else. That actually makes some logical sense. At other points in his emails, Kilimnik references how his outreach to Deripaska generally ran through an aide named “Victor” — or, as Kilimnik referred to him occasionally, “V.” (Time magazine has identified this aide as Victor Boyarkin, who, like Kilimnik, allegedly has ties to the Russian intelligence community.)

And at another point, Kilimnik says the person he met with for five hours had discussed “the future of his country.” That could be a reference to Russia, where Deripaska is from. But it seems just as likely (if not more) that it was a reference to Ukraine, whose Crimean Peninsula was annexed by Russia in 2014 and whose future was very much in the balance in 2016. A pro-Russian Ukrainian peace plan is the very subject that we now know Manafort and Kilimnik discussed at that Aug. 2 meeting.

(As for Kilimnik’s use of “his country,” it’s tempting to read something into that, too. Kilimnik was born in what was then Soviet Ukraine. But although Kilimnik is based in Ukraine, Mueller’s team has said he is a Russian citizen. That said, it’s not clear that “his country” meant to imply he was meeting with someone from a country other than his. It could have simply meant a different country than Manafort’s.)

Some media outlets have stated flat-out that the “black caviar” guy is, in fact, Deripaska. But as with all of our assumptions about the Russia investigation, it’s worth questioning this one. Exactly whom Kilimnik met and what messages he relayed are hugely important. Even if it’s not Deripaska, it could be someone just as problematic. But it all underlines just how much uncertainty remains about precisely what happened.