Rep. Ted Lieu, D-Calif., tweeted Saturday Special Counsel Robert Mueller "knows far more than people think" regarding his investigation into claims of Russian collusion in the 2016 U.S. presidential race.

"Important story below. Keep in mind no one was really aware of George Papadopoulos until his guilty plea was revealed. That tells us Special Counsel Mueller knows far more than people think. And Papadopoulos is cooperating with Mueller. The White House should be scared," Lieu tweeted Saturday.

Important story below. Keep in mind no one was really aware of George Papadopoulos until his guilty plea was revealed. That tells us Special Counsel Mueller knows far more than people think. And Papadopoulos is cooperating with Mueller. The White House should be scared. https://t.co/q4pDlxpRES — Ted Lieu (@tedlieu) December 30, 2017

Lieu's tweet comes after a New York Times story on Saturday claiming the Russia probe began following a drunken exchange in 2016 between George Papadopoulos, a campaign aide for President Donald Trump during his election campaign, and an Australian diplomat to Britain.

Papadopolous reportedly revealed to Alexander Downer, the Australian diplomat, that Russia had dirt on Democratic presidential contender Hillary Clinton. Papadopoulos indicated he had been told Russia had emails numbering in the thousands that could embarrass Clinton.

Two months later when Clinton's emails began appearing online, Australian officials notified their counterparts in the U.S. about the statements Papadopolous had made. That revelation eventually led to an FBI investigation and, ultimately, the naming of Mueller to the special counsel probe.

Papadopolous pleaded guilty to lying to the FBI and is now reportedly cooperating with Mueller's investigation.

Lieu is a member of the House Judiciary Committee, which has interviewed various Trump campaign associates in connection with lawmakers' inquiry into the Russia allegations.