Michael Cohen once billed himself as the “fixer” who could make Donald Trump’s most vexing problems disappear. Now, he’s poised to become one of the president’s biggest problems.

On Friday, the world got a glimpse of the sort of trouble Cohen may pose for his former boss, when the New York Times revealed he secretly taped a conversation with Trump two months before the 2016 election. The recording captures the two men discussing a payment to a Playboy model who claims to have had an affair with Trump.

The existence of that tape, which could be one of many, suggests Cohen’s greatest value to investigators may not be what he knows about Russia, but what he knows about Trump’s business and financial dealings, legal experts and former prosecutors told VICE News.

“Based upon what we know publicly, the legal issues surrounding Michael Cohen represent one of the biggest threats to the Trump presidency,” Renato Mariatti, a former federal prosecutor in Chicago, told VICE News. “It’s never a good thing when you’re caught on tape talking to a suspected criminal about the matters he’s being investigated for.”

On the recording revealed Friday, Trump can reportedly be heard giving Cohen advice about how to handle a potential payment to the company that bought the rights to Playboy model’s story, according to The Washington Post. The detailed discussion indicates both the close working relationship the two men had — and that Trump may find it difficult to distance himself from the actions of his longtime deputy.

“Of all the individuals on the planet that could potentially do significant harm to Mr. Trump, there’s little question that Michael Cohen is at, or very near, the top of that list,” Michael Avenatti, lawyer for Daniels, told VICE News. Stormy Daniels, whose real name is Stephanie Clifford, claims she was paid by Cohen for her silence right before the election, a decade after her affair with Trump.

“The legal issues surrounding Michael Cohen represent one of the biggest threats to the Trump presidency.”

Now the question is: what exactly does Cohen know?

Cohen is now under investigation by the U.S. Attorney’s office in the Southern District of New York, but he hasn’t been charged with any crime.

Legal experts and former prosecutors gave VICE News a rundown of the subjects investigators will likely want to ask him about — if he ultimately decides to cooperate.

The Affairs

The Playboy model, Karen McDougal, has said she had an affair with Trump over a decade ago that lasted roughly a year.

She was paid $150,000 in August 2016 by AMI, the parent company of The National Enquirer, for the rights to her story. But the Enquirer, which is owned by a friend of Trump’s named David Pecker, never published anything — effectively burying the story.

In their September 2016 conversation, Cohen and Trump discuss a plan by Cohen to attempt to purchase those rights from AMI for roughly $150,000, The Washington Post reported Friday, citing an unnamed person familiar with the recording. On the call, Trump tells Cohen to make sure he properly documents the agreement, and urges him to use a check — rather than cash — to preserve a record of the transaction, the person told the Post.

In a statement, Rudy Giuliani, Trump’s lawyer, confirmed the existence of the tape but told the Post that no payment was ever made. “Nothing in that conversation suggests that he had any knowledge of [the AMI payment] in advance,” Giuliani said. “In the big scheme of things, it’s powerful exculpatory evidence.”

“If Trump did know about it and directed Cohen, that could link Trump to campaign finance violations.”

But McDougal isn’t alone. Cohen has admitted to organizing a $130,000 payout and nondisclosure agreement for adult film actress Stormy Daniels, who has said she slept with Trump in 2006. Trump has said he didn’t know that Cohen made the payment at the time it happened.

Cohen reportedly raised the money to pay Stormy from a home equity line of credit, which might be fraud if he misled the bank about the purpose of the funds, according to Mariotti. If so, and Trump knew about it, that could mean legal trouble for Trump, too, Mariotti said.

Adult film actress Stephanie Clifford, also known as Stormy Daniels, speaks to media along with lawyer Michael Avenatti (R) outside federal court in the Manhattan borough of New York City, New York, U.S., April 16, 2018. REUTERS/Lucas Jackson/File Photo

The payouts to women for their silence could constitute improper campaign contributions, and may mean trouble for Trump depending on the circumstances and how deeply he can be shown to have been involved, according to Mimi Rocah, a former prosecutor for the Southern District of New York.

“If Trump did know about it and directed Cohen, that could link Trump to campaign finance violations,” Rocah said, referring specifically to Cohen’s payment to Stormy Daniels. “But they’d have to show it was for the benefit of the campaign, and not just personal. It can’t just be, like, ‘I don’t want my wife know.’”

For an example, look no further than former Democratic presidential candidate John Edwards, who was indicted in 2011 on charges of using illegal campaign donations to conceal his mistress from voters.

Just days before the election, Cohen created a shell company called Essential Consultants LLC to pay Daniels.

After Trump entered the White House, Cohen used the same company to receive millions in payments from international corporations who wanted insight into the Trump administration, including AT&T and Swiss drugmaker Novartis.

Cohen also scored a $1 million consulting contract from a U.S. hedge fund closely linked to a Russian billionaire with longstanding Kremlin ties named Viktor Vekselberg, in a deal that’s already drawn the scrutiny of federal investigators.

Investigators will likely want to know whether Trump knew about these payments, and whether any of them involved any kind of explicit promises for favorable treatment in exchange for the payments, said Harry Sandick, a former prosecutor for the Southern District of New York.

“Did he enter into any of those consulting agreements with the president’s knowledge?” Sandick asked. “It would have to be more than just Cohen saying, ‘Hey, I’ll get your voice heard,’ because that would be legal. There would have to be some sort of a quid pro quo.”

The Organization

Cohen recently scrubbed his position as executive vice president and senior counsel at the Trump Organization from his LinkedIn page in a move received as creating distance between himself and Trump.

But pressing delete doesn’t scrub years of insights from inside the Trump Org. Cohen appears to have held a wide-ranging portfolio during his tenure under Trump, which included serving as the point man for potential projects in Russia and elsewhere in the former Soviet Union.

Cohen worked on setting up a Trump Tower project in Moscow right up until just weeks before the presidential primaries kicked off, and he was involved in scoping out projects in the former Soviet republic of Georgia and in Kazakhstan.

Prosecutors will likely want to ask whether all those far-flung business dealings were carried out by the book. And if they weren’t, investigators will want to ask whether Trump knew about it, Mariatti told VICE News.

Cohen’s expansive role as Trump’s all-purpose fixer suggests he might know about unorthodox — and, potentially, improper — modes of doing business at the Trump Organization, observers said.

To name just one potential pitfall, businessmen operating abroad are often cautioned not to violate the Foreign Corrupt Practice Act, which in essence forbids American citizens from paying bribes to foreign government officials to win business.

“If that happened, and if there were internal discussions of that happening, that would be a problem,” said Jens David Ohlin, vice dean at Cornell Law and an expert in international criminal law.

The Trump Organization has explored business opportunities in countries with low rankings on Transparency International’s global Corruption Perceptions Index — Panama and India, to name a few.

The Trump Tower meetings

Another crucial question for Cohen will be what he knew about the Trump campaign’s links to Russia during the campaign.

One event he might be able to shed light on: The Trump Tower meeting in June 2016 between the top brass of the Trump campaign and a lawyer from Russia who’d been billed as having dirt on the Clinton campaign.

“You’re either in or you're out — or else you’re really going to screw yourself.”

Cohen told ABC News’ George Stephanopoulos in early July that taking the meeting was a bad idea. And he pointedly refused to say whether Trump might have known about it in advance.

“I believe it was a mistake by those from the Trump campaign who did participate,” he said. "It was simply an example of poor judgment.”

Cohen has repeatedly denied the claim that first emerged in the infamous Steele dossier, compiled by former U.K. intelligence officer Christopher Steele, that he personally traveled to Prague to coordinate Russia’s involvement in the presidential campaign.

On the heels of Friday’s bombshell, the stakes of Cohen potentially reaching a cooperation agreement with prosecutors seemed to ratchet up even higher.

And if he does accept a deal, prosecutors will expect him to divulge everything he knows, Rocah said.

“The worst thing you can do is halfway cooperate,” Rocah said. “You’re either in or you're out — or else you’re really going to screw yourself. Someone who pleads guilty to something, and then messes it up, is in a worse position than if they never pleaded guilty in the first place.”