CNN  — 

President Donald Trump is concerned about whether his son Donald Trump Jr. might have exposure in the special counsel’s Russia investigation, leading to his increasingly frenzied public agitation over Robert Mueller, sources close to the White House tell CNN.

Trump has been concerned for months now that the Mueller probe could reach his family, and potentially his son-in-law Jared Kushner, but his focus has turned to his namesake in recent weeks, one person who speaks with Trump frequently tells CNN. This is one of several reasons Trump has upped his public attacks on Mueller, because he doesn’t want him touching his family, the person adds.

Trump Jr. and his attorney have insisted he has always told the truth. But his claims publicly and to the Senate Judiciary Committee that he never told his father about the 2016 Trump Tower meeting with a Russian attorney promising dirt on Hillary Clinton have been contradicted by others in Trump’s orbit. Michael Cohen, Trump’s longtime attorney and former fixer, is said to be prepared to testify that the President knew about the Trump Tower meeting ahead of time, sources with knowledge of the matter told CNN. Trump has denied knowing about the meeting before it happened.

Others who have been close to the President – including his former White House communications director, Anthony Scaramucci, and former White House chief strategist Steve Bannon — have suggested the President at the very least knew shortly after the fact.

The President denied that he is worried about the Trump Tower meeting in a Twitter post Sunday morning.

“Fake News reporting, a complete fabrication, that I am concerned about the meeting my wonderful son, Donald, had in Trump Tower,” Trump wrote on Twitter. “This was a meeting to get information on an opponent, totally legal and done all the time in politics - and it went nowhere. I did not know about it!”

The explanations about the reason for the meeting from Trump Jr., the White House and the President’s legal team have changed and been contradictory over time. In a statement to The New York Times last summer, Trump Jr. said the meeting was primarily about adoption policies, and spokespersons for the President repeatedly denied that Trump was involved in crafting it. But it was revealed in June of this year that a letter from the President’s attorneys to Mueller said Trump did in fact “dictate” the statement – raising the question of why Trump tried to hide the true premise of the meeting.

Asked about CNN’s latest reporting on the President’s mindset, a source close to Trump Jr. said he’s not concerned and maintains he did nothing wrong.

Earlier this week, the chairman of the Senate Judiciary Committee, Republican Chuck Grassley of Iowa, told CNN that if Trump Jr. “misled the committee, he’s lying to Congress. That’s a crime. And that’d be up to the prosecutors, not me.”

The President this week has for the first time said that Attorney General Jeff Sessions “should stop” the Mueller probe. He has also in recent weeks increased the number of times he has criticized Mueller personally.

Earlier this week, Trump Jr.’s lawyer, Alan Futerfas, issued a statement after CNN first reported on what Cohen was prepared to say in testimony.

“We have investigated this matter for over a year and are in command of the facts,” Futerfas said. “We are fully confident of the accuracy and reliability of the information that has been provided by Donald Trump Jr. in the various investigations.”

The White House declined to comment regarding the President’s concern about his son, instead referring questions to Trump’s legal team.

When asked for reaction, Trump’s lead attorney Rudy Giuliani told CNN in a statement:

“Just not so. After over a year or more of investigating … there is no evidence of any wrongdoing on his part or for that matter POTUS. Nothing has changed. We are not worried about Michael Cohen because he has no knowledge of wrongdoing and has recorded it in one version or another so often that he can’t be believed or relied on.”

The Washington Post earlier Saturday reported about some of Trump’s concerns about the effects of the investigation on Trump Jr.

CNN’s Dana Bash contributed to this report.