Congressional Republicans on Sunday called for Democrats John Podesta and Rep. Debbie Wasserman Schultz to provide further answers about their party paying for a dossier on President Trump’s alleged ties to Russia, after telling Senate investigators last month that they had no knowledge of such payments.

Wasserman Schultz is the former chairman of the Democratic National Committee, and Podesta was the chairman of Hillary Clinton’s 2016 presidential campaign. Both groups purportedly paid millions for research that led to the dossier, The Washington Post reported last week.

South Carolina Rep. Trey Gowdy, chairman of the House Oversight Committee, suggested on “Fox News Sunday” that the DNC paying a law firm for so-called opposition research connected to the dossier was tantamount to money laundering.

“I'm not an election law expert, but the good news is you don't have to be, to understand the absurdity of believing that you can launder all of your campaign money by just hiring a law firm,” said Gowdy, a former federal prosecutor. “So I’m interested in that.”

He also seemed to question Podesta and Wasserman Schultz telling the Senate Intelligence Committee last month that they didn’t know who paid for the dossier.

“I am also interested in sharing some memory tricks with folks at the DNC because no one can remember who paid $10 million to a law firm to do oppo research,” Gowdy said. “I find that stunning. $10 million and no one can remember who authorized it, who approved it, who said, ‘This is a really good idea.’”

When questioned about the issue by Fox News last week on Capitol Hill, Wasserman Schultz said only: “I wasn’t aware of the arrangement at all.”

Also on Sunday, Maine GOP Sen. Susan Collins, a member of the Senate Intelligence Committee, said Podesta and Wasserman Schultz “absolutely need to be recalled” before the panel.

“It's difficult to imagine that a campaign chairman, that the head of the DNC would not know of an expenditure of this magnitude and significance,” Collins said on CBS’ “Face the Nation.”

Podesta's attorney Marc Elias, who worked for the law firm that brokered the dossier funding, sat next to Podesta during his Senate appearance last mont, according to CNN. Collins also said Sunday that Elias should be questioned, too.

California Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, on Sunday declined to answer on ABC’s “This Week” whether the DNC and Clinton campaign should have disclosed earlier their stake in the dossier.

“I can't answer that,” he said. “I certainly would have liked to know who paid for it earlier, but nonetheless, that's just one factor to be considered.”

Fox News' Jason Donner and The Associated Press contributed to this report.