The controversy surrounding top Trump national security adviser Michael Flynn reached a boiling point on Monday as a new report from the Washington Post shows that the White House was warned by the Obama administration about Flynn’s ties to Russia late last month.

According to the Post, Sally Yates, who most recently served as acting Attorney General before being fired by Trump, told the new administration that Flynn “was potentially vulnerable to Russian blackmail.”

More from the report:

In the waning days of the Obama administration, James R. Clapper Jr., who was the director of national intelligence, and John Brennan, the CIA director at the time, shared Yates’s concerns and concurred with her recommendation to inform the Trump White House. They feared that “Flynn had put himself in a compromising position” and thought that Pence had a right to know that he had been misled, according to one of the officials, who, like others, spoke on the condition of anonymity to discuss intelligence matters.

According to the Washington Post, it’s “unclear what the White House counsel, Donald McGahn, did with the information.”

The Post report comes shortly after Democrats in the House Oversight Committee, in a letter to Chairman Jason Chaffetz, demanded an immediate investigation into Flynn’s connections to Russia.

In the letter, Democrats slammed the Republican’s “partisan stonewalling” and urged the chairman to conduct a “robust” and “bipartisan investigation” into Flynn.

Part of the letter sent to Chaffetz by Democrats on the committee:

Controversy has been swirling in full force around Flynn in recent days after it was revealed that, prior to Trump being sworn in, he made a pledge to Russia that the sanctions imposed on them by the Obama administration would be lifted.

“Flynn reportedly assured the Russian ambassador to the US that sanctions placed on the country by President Obama would be eased once President Trump took office,” the New York Post reported. “Compounding the situation, Vice President Mike Pence repeated Flynn’s claim in media interviews.”

Top Republicans, including Rep. Chaffetz, recently joined Democrats last week to condemn Kellyanne Conway and encourage the U.S. Ethics Office to penalize her after she promoted Ivanka Trump’s clothing line live on national television. When it comes to Flynn, however, Chaffetz has been reluctant to act, even though his actions are more damning than Conway’s.

As the calls for Flynn to be investigated, or even be fired, grow louder and more bipartisan, Chaffetz may find himself with no choice.

One Republican congressman, Mike Coffman of Colorado, said in a statement released Monday night that Flynn should “step down immediately” if he misled the president on his ties to Russia.

Statement via Coffman’s Twitter:

It’s unclear whether the president even cares Flynn had been in communication with the Russians prior to Trump taking office. After all, Trump himself has been stubbornly reluctant to say anything critical about Russia, while eagerly lashing out at U.S. allies. He also has been anything but transparent when it comes to his own ties to Moscow.

In any other White House, having such ties to Russia, as Flynn does, would likely lead to an immediate firing. In an administration led by Trump – who was essentially put in the White House by Russia – all bets are off.

  Donald Trump, Michael Flynn, Obama Administration, Russia, Sally Yates