(CN) – President Donald Trump’s former attorney Michael Cohen said Thursday that the president knew in advance of a June 2016 Trump Tower meeting between his son Donald Trump Jr. and a Russian lawyer who offered dirt on Democratic presidential nominee Hillary Clinton, according to several media sources.

A source told CNN Thursday night that Cohen, along with others, was present when Trump Jr. told his father of the Russians’ offer and reportedly gave the meeting his approval. Cohen, according to sources, does not have audio recordings of the conversation but is willing to tell the details to special counsel Robert Mueller.

President Trump and White House officials have repeatedly denied that the president knew about the meeting. Along with Trump Jr., former campaign manager Paul Manafort and son-in-law Jared Kushner met with Russian lawyer Natalia Veselnitskaya concerning an emailed pitch to Trump Jr. “as part of Russia and its government’s support for Mr. Trump.”

Cohen has been the center of attention since the FBI raided his home, hotel and office in April, acting on information uncovered by Mueller’s investigation into possible collusion between the Trump campaign and Russia.

President Trump’s current attorney, Rudy Giuliani, said in a CNN interview Thursday night that Cohen had no credibility.

“He’s been lying all week, he’s been lying for years,” Giuliani said, calling Cohen a “pathological liar.”