Congress wants to talk to Trump CFO Allen Weisselberg. Here’s why that matters.

Michael Cohen, Donald Trump’s former personal attorney, testified before Congress that he couldn’t delve too deeply into Trump’s shady financial dealings. He’s not an accountant, Cohen said, but he knows someone who could help.

“Are there other people that we should be meeting with?” Del. Stacey Plaskett, a Democrat representing the U.S. Virgin Islands, asked Cohen as he sat before the House Oversight Committee on Wednesday.

“Allen Weisselberg,” Cohen responded, name-dropping the chief financial officer for the Trump Organization. Weisselberg was reportedly given immunity in August to testify against Cohen, although NBC reported Wednesday that he’s not cooperating with investigators. Cohen answered questions from lawmakers hoping to probe into Trump’s finances with Weisselberg’s name several times.

Now, the House Intelligence Committee wants to hear from him. The committee “anticipates bringing in Mr. Weisselberg,” a person familiar with the deliberations told VICE News Thursday. And the chair of the House Oversight Committee has said that panel will “probably” seek to question Weisselberg.

The CFO came up often throughout Cohen's hours-long testimony as a person familiar with Trump’s tax returns, the partial orchestrator of hush-money payments to the adult film actress Stormy Daniels, and the confidant most familiar with how the president manipulated the worth of his assets.

“It’s almost like [Cohen] went out of his way to mention his name and say he has the records,” Dan Guthrie, a white-collar defense attorney and former federal prosecutor, said.

Read more: Cohen's testimony is bad news for Don Jr.

Although Wednesday was the first time many Americans heard the name Weisselberg, he has long been the source of fascination for those closely watching the investigations into Trump. Here’s what you need to know about the little-known financier who holds the keys to Trump’s financial dealings.

Weisselberg has worked with the Trump team for decades, and generations: first for Trump’s father, Fred, in the 1970s, then for Donald Trump. When Trump stepped away from the day-to-day management of his business, he turned it over to three trusted insiders: his sons Don Jr. and Eric — and Weisselberg. The 71-year-old financier has reportedly overseen the preparation of Trump’s tax returns and personal purchases — on top of running the Trump firm’s finances.

He has negotiated loans on Trump’s behalf and is a co-signer on many of his personal accounts, according to Bloomberg Businessweek.

Simply put, it would be difficult to keep a secret from the person who has tracked money flowing in and out of Trumpworld for decades.

“I think Weisselberg could sink Trump,” Charles A. Intriago, a former federal prosecutor and a money-laundering expert, told VICE News in August, after news broke of Weisselberg’s immunity deal with SDNY.

Cohen said the hush-money payments to women who claimed they had sex with Trump were orchestrated in Weisselberg’s office in Trump Tower ahead of the 2016 presidential election.

On Wednesday, Cohen showed Congress a check for $35,000 that was signed by Trump’s son Don Jr. and Weisselberg to reimburse Cohen for a portion of the $130,000 he paid to keep Stormy Daniels — legal name Stephanie Clifford — from talking to the press about an alleged 2006 affair. The check was one of 11 co-signed by Weisselberg, Cohen said.

“It would either be Eric Trump, Donald Trump Jr., and/or Allen Weisselberg. But always Allen Weisselberg on the check,” Cohen said.

Weisselberg was mentioned in a conversation between Cohen and Trump that Cohen secretly recorded. The discussion concerned a plan to establish the shell company Cohen used to pay off former Playboy model Karen McDougal, who also said she had an affair with Trump in 2006.

Read more: 5 things you need to know about Cohen's testimony.

Cohen is heading to prison for three years, in part because those payments violated campaign finance laws. “I’ve spoken to Allen Weisselberg about how to set the whole thing up,” Cohen told Trump in the recording. “So, I’m all over that. And I spoke to Allen about it.”

Trump has denied affairs with both women.

Weisselberg’s knowledge of the true state of Trump’s financials will also likely be of interest to Congressional investigators. On Wednesday, Rep. Alexandria Ocasio-Cortez, a Democrat from New York, pushed Cohen for information regarding allegations that Trump inflated the worth of certain assets to insurance companies, while deflating the value of other assets like his golf courses, to pay fewer taxes. And again, Cohen suggested Weisselberg would have information about that.

“As an investigating prosecutor, you’re always very, very, very interested in the money,” said Patrick Cotter, a former federal prosecutor and white-collar defense attorney. “And Weisselberg is the guy who apparently has a better sense of the money swirling around Trump and his organization than anybody.”

It depends on if and when he's asked to testify before Congressional committees, and whether he’ll agree to appear.

Rep. Elijah Cummings, a Democrat from Maryland and chair of the Oversight Committee, said his panel would “probably” seek to question Weisselberg so long as it didn’t overlap with dueling investigations from special counsel Robert Mueller and the U.S. Attorney’s Office for the Southern District of New York. Cummings also added that if a name was mentioned repeatedly in Cohen’s testimony, there was a “good chance” his committee would want to hear from them. Law enforcement has reportedly subpoenaed Weisselberg in the past, although the scope of what he discussed — if anything at all — isn’t quite clear, and there have been conflicting reports about whether he’s cooperated with the feds to discuss payments made by Cohen to keep the two women quiet.

When asked whether Weisselberg had betrayed him when he was granted immunity, Trump told Bloomberg News: “100 percent he didn’t.” “He’s a wonderful guy,” Trump added.

Whether he’ll actually appear before Congress is another question, Cotter said, especially since the inquiries into his financial dealings with Trump could be wide-ranging and go beyond the scope of what he might have been asked by prosecutors with the Southern District. It would not be surprising if he pleaded the Fifth Amendment to avoid incriminating himself, Cotter added. He hasn’t been accused of any wrongdoing, either.

“If I was his lawyer, I’d probably very strongly suggest he take the Fifth,” Cotter said.

Cover: U.S. President-elect Donald Trump and his son Donald Jr. arrive for a press conference at Trump Tower in New York, as Allen Weisselberg (C), chief financial officer of The Trump, looks on. (Photo by Timothy A. CLARY / AFP) (Photo credit TIMOTHY A. CLARY/AFP/Getty Images)