On Tuesday, Michael Avenatti produced a bombshell allegation: A corporate fund that seemed to be controlled by Russian oligarch and close Putin ally Viktor Vekselberg had paid $500,000 to Michael Cohen’s bank account in the initial months of Trump’s presidency. The New York Times and NBC quickly verified the core of Avenatti’s claim. The firm, meanwhile, denied that Vekselberg was involved in the payment, claiming Cohen was hired as a consultant on real estate and other investment opportunities.

Talk of a smoking gun here would be premature. But the new evidence provides a preview of what a smoking gun might look like and a road map for how to find it in the developing case against President Donald Trump. These allegations are not just about a hush payment and campaign finance felonies. This is a significant step toward establishing quid pro quo bribery and conspiracy against the United States.

First, Vekselberg recently increased his share to 26.5 percent in the aluminum firm Rusal. That firm was owned by Oleg Deripaska, the Russian billionaire whose ties to former Trump campaign manager Paul Manafort are under scrutiny by special counsel Robert Mueller.

Two of Vekselberg’s American partners, meanwhile, donated more than $1 million to Trump’s inaugural committee and Vekselberg also had business ties to Trump’s Commerce Secretary Wilbur L. Ross.

Now, Congress has been legislating tougher sanctions against Putin and Russia over the past year by sweeping, close-to-unanimous bipartisan majorities. But the Trump administration has been softening or delaying those sanctions at every turn. Last month, the Treasury’s Office of Foreign Assets Control finally implemented congressional sanctions against Deripaska and Rusal, in addition to other Russians. The Treasury Department cited allegations that Deripaska ordered the murder of a businessman and had links to a Russian organized crime group. But on April 23, the Trump administration announced major delays on implementation, “slow-rolling” the sanctions seemingly to give Rusal time to minimize the damage and to appeal the sanctions. Treasury gave Rusal an extension to next October, and Reuters reported the department would “consider lifting [the sanctions] if United Company Rusal PLC’s major shareholder, Russian tycoon Oleg Deripaska, ceded control of the company,” which he soon did. “Given the impact on our partners and allies, we are … extending the maintenance and wind-down period while we consider RUSAL’s petition,” Treasury Secretary Steven Mnuchin said in a statement.

Given the outrageous conduct of Putin and Deripaska, and given the almost unanimous votes in Congress to impose tough sanctions, these accommodations should have been considered stunning. As of Tuesday night, they stink to high heaven.

And the question must be raised: Was there a quid pro quo understanding between Vekselberg and Trump associates in January 2017? It is crucial to remember here what was happening in December 2016 and January 2017 in regard to Russia sanctions. Here’s what I summarized in an earlier Slate piece on Kushner, Qatar, and Russian money: The Steele dossier alleged that Russians had made a deal with Trump associates for the Russians to sell Rosneft, the massive state energy company, and use the commissions to give Trump associates payments under the radar, in return for lifting or softening sanctions. The Rosneft sale went through in December 2016, a month after the election, coinciding with Jared Kushner, Michael Flynn, and Carter Page’s various alleged communications with Russians. Just eight days before this oil megadeal, Flynn and Kushner met Russian Ambassador Sergey Kislyak at Trump Tower, and Kushner reportedly proposed a secret communication link with the Kremlin through the Russian embassy. Then, a few days after the Rosneft deal, Kushner met Sergey Gorkov, chairman of Russia’s government-owned VE Bank, or VEB, and Putin’s close confidant.

Analysts have described VEB as Putin’s “private slush fund,” a source of money independent from official Russia budgeting. VEB is under strict U.S. sanctions. Gorkov reportedly flew to Japan to meet with Putin practically immediately. On Dec. 29, President Barack Obama ordered new Russian sanctions for election hacking and interference—and Flynn reportedly had five calls with Kislyak. We later learned that they discussed Russian sanctions after Flynn pleaded guilty to lying about this fact to federal investigators. Trump tweeted about Putin the next day, calling him “very smart” for not responding to Obama’s sanctions before Trump has had a chance to transition into office.

We’ve now learned, in the very next month after the Kushner/Flynn back-channel contacts with Russia, the Vekselberg-connected payments to Cohen began. And they occurred, inexplicably enough, after the Steele dossier was published. Again, this is all clearly now a subject of Mueller’s probe. As the New York Times first reported last week, Mueller’s agents questioned Vekselberg when he flew into New York earlier this year. CNN reported on Tuesday that they asked him about these particular payments. What might be the plausible innocent explanation for a Putin-associated Russian oligarch, to use Rudy Giuliani’s phrase, “funneling” money to Trump’s personal lawyer through a fund used to pay hush money to one or more women and as that oligarch was due to benefit from Trump’s sanction policies? Maybe they have an explanation, but it’s hard to imagine it, and it’s hard to imagine how persuasive a jury would find it.

The Avenatti document, meanwhile, suggests a road map for trying to substantiate this hypothetical. The first part of Avenatti’s summary offers more detail for the allegation that Cohen may have committed bank fraud, misrepresenting the reasons for opening his bank account. I’ve explained in an earlier piece how this is one of several federal and state crimes that Cohen is potentially facing. He is also still on the hook for possible campaign finance felonies, even if one accepts all of Giuliani’s spin about reimbursement. Furthermore, Avenatti suggests that California has jurisdiction over these possible crimes, opening up another set of state and federal prosecutors who could potentially bring charges. Which is all just to say, there is more pressure on Cohen to cooperate with Mueller and other prosecutors than ever. If he were to flip, he would presumably have to provide insight into what these payments were for.

This new information about Vekselberg potentially puts pressure on other witnesses as well. Who else in Trump’s orbit had contact with Vekselberg, and might they have more information about the communications and intent behind the payments? Rick Gates, Manafort’s former deputy who has pleaded guilty to conspiracy and lying to investigators, was also helping with the transition as these events were unfolding. What has Gates already told Mueller in exchange for a plea deal and what might he have to say now? Vekselberg was also at the Moscow dinner attended by Putin and Michael Flynn. What has Flynn told Mueller? One road to proving any conspiracy now clearly goes through Vekselberg, those who were in contact with him, and those who may have been paid off by him.

Finally, even if Trump denies that he knew about any of the questionable Cohen payments, he still might not be off the hook. If it can be demonstrated that he found out later about an illegal payment but sought to cover it up, Trump might have committed one of the following felonies: a) being an accessory after the fact (18 U.S.C. 3), b) misprision of a felony (18 USC 4, especially by a public official), and c) obstruction of justice.

I’m setting aside the other details being reported about payments from AT&T, Novartis, and Korea Aerospace to Cohen. Pay-to-play is scandalous, but federal law only prohibits a surprisingly narrow set of payments as “pay-to-play” violations, and it is not clear that any of these payments would violate those regulations. After the Supreme Court’s unfortunate decision in McDonnell in 2016, it is exceedingly difficult to prove quid pro quo for bribery.

Just as it is difficult to prove quid pro quo bribery by these firms, it would be difficult to prove bribery for the Russian payments, even if that’s what these are. But they strengthen the proof for probable cause, which is the standard for warrants and indictments. And any forthcoming indictments and warrants stemming from this line of inquiry will lead to increasing pressure on apparent co-conspirators, like Cohen, who in turn can help a jury, the public, and perhaps Congress, find proof beyond a reasonable doubt.