With a pivotal figure in the Trump-Russia saga summoned to testify before the Senate, and another one again denying all wrongdoing, a key senator is saying the only way to determine the truth about President Trump and the Kremlin is to follow the money.

“The wordsmithing on the follow-the-money issue in particular ought to really set off the bells,” Sen. Ron Wyden, an Oregon Democrat on the intelligence committee, told The Daily Beast a day after White House senior adviser Jared Kushner met with the panel’s Russia inquiry.

“You’re up against a White House that is I think every day moving closer to a constitutional crisis,” Wyden said about his committee’s investigation.

Kushner’s combative public statement on both his meetings with Russian officials and Kremlin-connected Russians and his initial failure to disclose them on his security concerns did not satisfy Wyden. For him, it raised more questions than it answered, particularly about the role Russian money has played in Kushner’s business dealings.

The president’s son-in-law emphasized on Monday that he has “not relied on Russian funds to finance my business activities in the private sector”—a formulation that reflects “careful lawyering,” Wyden said.

“That is a world record in terms of careful lawyering. It didn’t say ‘I have no business dealings with the Russians.’ He didn’t say ‘I’ve never received investments from Russian companies.’ Of course, ‘rely’ can mean all kinds of things, but when the president won’t release his tax returns, when the family says as far back as 2008 much of their portfolio involved Russian investments, this something I’m going to bear down on,” Wyden told The Daily Beast on Tuesday.

Wyden’s “2008” reference is to Donald Trump Junior, who told a real-estate conference that year that “Russians make up a pretty disproportionate cross-section of a lot of our assets,” adding: “We see a lot of money pouring in from Russia.”

While Kushner just wrapped his first round of interviews with congressional investigators—he met with the House intelligence committee on Tuesday—another had been highly anticipated to testify tomorrow: Paul Manafort, the former Trump campaign chairman who did extensive political work in Ukraine on behalf of Russia-sponsored politicians. Manafort is now under investigation for potential money laundering by special counsel Robert Mueller, the Wall Street Journal reported last week.

Manafort on Tuesday received a subpoena from the leaders of the Senate Judiciary Committee to testify at a hearing about foreign influence in U.S. elections scheduled for Wednesday morning. But after this piece went to press, the judiciary committee announced that Manafort had begun turning over documents and working in “good faith” on an interview date with the committee, obviating—for now—his public testimony.

After withdrawing their subpoena, the committee’s leaders, Republican Chuck Grassley and Democrat Dianne Feinstein, said of Manafort, “Cooperation from witnesses is always the preferred route, but this agreement does not prejudice the committee’s right to compel his testimony in the future. Wyden urged his colleagues to push for Manafort, Kushner and all others connected to the Russia allegations to face questions in public—without prior deals to immunize their testimony against potential criminal charges.

“It’s critically important that Manafort and all of the people you’re hearing about testify in public. I’m sure they’ll all try to be immunized and the like, and it’s the job of our committee to ensure that these key individuals are brought up before the Congress and that we work with Bob Mueller in a way to deal with the various confliction issues,” he said.

“It’s critical that [Manafort] be in public and he not be immunized. I don’t think any of them should be immunized. I think we need to hear from them in public and they not be immunized at this point.”

Renato Mariotti, a former federal prosecutor, said that he would not advise a client to testify before Congress on an issue like Russia without a grant of immunity from legal liability.

“They should not be testifying without immunity. The fact that Kushner decided to grant an interview with Congress tells me his attorneys, after reviewing his documents, felt comfortable with him answering questions on certain topics and that his answers would not create additional liability for him,” Mariotti told the Daily Beast.

Wyden would not comment on any non-public aspect of the intelligence committee’s Kushner interview, nor the Manafort interview.

While Wyden continued to have questions for Kushner, the co-chair of the House intelligence committee’s Russia inquiry does not.

“ He was completely cooperative, straightforward. His answers were forthcoming and complete. And he satisfied all of my questions,” Texas Republican Mike Conaway said Tuesday morning following Kushner’s interview.

Trump has said that Mueller would be out of line to look into his finances outside of the campaign, despite earlier indications of Russian financial connections. He remains dubious of the U.S. intelligence assessment that the Kremlin interfered in the 2016 election for his benefit, according to communications chief Anthony Scaramucci. And he continues to flirt with firing Mueller, to include musing about Attorney General Jeff Sessions’ job insecurity over his recusal in the Russia probe—something many on Capitol Hill think would be an opening act to firing Mueller.

Not looking into Trump’s finances is “a complete nonstarter,” Wyden said. “We need to know what financial connections there are.”

—Additional reporting by Andrew Desiderio.